- Introduction
The scope of labour law legislation is expanding day by day; the provisions regulating the employer – employee relationship is becoming more detailed both at the normative level and through judicial case law. Parallel to this, the principles of written form, clarity and predictability have gained increasingly prominent importance in the resolution of disputes concerning working conditions. However, despite these developments, it is difficult to say that certain old habits and practices that have become established in working life have been completely abandoned. In particular, changes arising in practice after the establishment of the employment relationship regarding the nature of the work, wages and wage-related entitlements, and the working order, are still frequently implemented without being subject to an explicit and written agreement between the parties.
As a reflection of this practice, the fact that employees do not expressly object to changes made by employers in working conditions or continue to work by de facto adapting to the changed conditions, has, over time, given rise to a legally controversial phenomenon of “acceptance.” At this point, one of the main areas of debate in practice is whether the employee’s silence in the face of such changes or de facto adaptation to them necessarily means that the change has been accepted.
Article 22 of Labour Act No. 4857 (“the Act”) subjects the possibility of making a substantial change in working conditions to a clear procedure. Pursuant to the said provision, changes in working conditions which are fundamental in nature and may result in adverse consequences for the employee can be implemented only if the employer first notifies the employee in writing and the employee then accepts such change in writing within six working days. In this respect, the Act is based on the principle that changes in working conditions are to be shaped not tacitly, but by explicit declarations of intent.
However, in practice, despite this clear regulation, it is frequently encountered that the procedure stipulated for substantial changes is not followed, while the employee continues to work for a long period of time without raising any objection. Such situations give rise to legal debates concentrated around the concepts of “tacit acceptance” or “implied consent.” At this point, the Court of Cassation seeks a balance between, on the one hand, upholding the strictness of the written form requirement in Article 22 and, on the other, taking into account the effect of the principle of good faith in concrete cases.
In this study, the circumstances under which the employee’s de facto adaptation with substantial changes in working conditions may be considered implied consent, and the circumstances under which such acceptance cannot be inferred, will be examined systematically in the light of recent case law of the Court of Cassation. In doing so, it is aimed to increase foreseeability regarding the legal consequences of remaining silent for both employers and employees, and to more clearly identify the risk areas frequently encountered in practice.
- The Concept of Fundamental Change in Working Conditions and Its Legal Consequences
All mutual rights and obligations that maintain the validity of the employment contract concluded between the parties are defined as working conditions. The Court of Cassation evaluates within the scope of working conditions the employee’s obligation to work, the employer’s duty to pay remuneration, the place and time of performance of work, working hours, annual leave periods, wage supplements, rest breaks and many other elements.[1] In this respect, working conditions are not limited to the principal performances under the contract, but encompass all elements determining how the employment relationship is actually conducted.
In general terms, a substantial change may be defined as “changes in the essential elements of working conditions that may result in adverse consequences for the employee.” The boundaries and elements of the concept of substantial change are not defined in statutory legislation; therefore, the change in dispute must be evaluated separately in the context of each concrete case. However, in its settled case law, the 9th Civil Chamber of the Court of Cassation, in parallel with the above definition, takes as its basis the criterion of “whether the employee’s situation has been aggravated.”[2] Accordingly, changes that are in the employee’s favour, or even if they are to the employee’s detriment but remain within the scope of the employer’s management prerogative, are not considered substantial changes.
Under the repealed Labour Act No. 1475, substantial changes in the provisions of the employment contract were not subjected to a specific procedure. In that period, employees were essentially afforded only the possibility of termination with just cause in response to unilateral changes made by the employer. In other words, employees were placed in a passive position vis-à-vis the change by the employer and were not given any option other than accepting the change or terminating the employment contract. This approach often led employees either to be compelled to accept the change de facto or, in the case of termination, to obtain their rights such as notice and severance pay only after lengthy disputes.
This approach was abandoned with Article 22 of Labour Act No. 4857, which laid down the procedure to be followed in the event of a substantial change. Pursuant to said regulation, in order for substantial changes to be implemented, the employer must notify the employee in writing, and the employee must accept such notification in writing within six working days. Changes that the employee does not approve in writing within this period shall not be binding upon the employee; and in the face of changes unilaterally implemented by the employer, the employee shall be granted the possibility of termination with just cause.
In this regard, the Act grants employees a third option beyond the binary “accept or terminate”; it explicitly safeguards the “right to refuse a substantial change.” Conversely, for employers, where the proposed change is based on a valid reason, the Act affords the possibility of terminating the employment contract for a valid reason if the employee does not accept the change. Thus, Labour Act No. 4857 aims to establish a more balanced and foreseeable regime for changes between the parties.
As can be seen, the Act is based on a written, explicit and traceable communication model between the parties, regardless of the ultimate fate of the proposed change. For this reason, situations in which declarations are made openly, rather than tacitly, are essential. However, the practical reality does not always develop in this way. From time to time, even where the procedure envisaged in the Act is not followed in relation to the service of the change proposal or the employee’s declaration of intent, disputes arise in which the change is nevertheless deemed to have been accepted.
In this context, the first kind of situation referred to as “implied consent” or “tacit acceptance” arises where the employee approves the change proposal in writing after the expiry of six working days. In doctrine and in the practice of the Court of Cassation, this is not considered a late acceptance of the initial offer but a new offer. Where the employer accepts this new offer, the change is deemed to have validly come into existence. In such cases, written confirmation by the employer is not separately required; the continuation of the employment relationship is interpreted as tacit acceptance of the late approval.[3]
The more frequent and contentious situation in disputes, however, is where the employee, despite not expressly consenting to the change, continues the employment relationship. The prevailing view in doctrine and in the case law of the Court of Cassation is that not every change to which the employee de facto adapts, despite not having given written consent, can be qualified as implied consent. The nature of the change implemented, the other documents signed in the period following the change, and the period of work after the change are such elements that become determinative in the assessment of implied consent. In this framework, the boundaries of implied consent constitute a delicate balance shaped by the case law of the Court of Cassation.
- The Limits of Implied Consent in the Light of Court of Cassation Case Law
a. Cases Where the Employee’s De Facto Adaptation Is Not Considered Implied Consent
In cases where substantial changes in working conditions are unilaterally implemented by the employer, the fact that the employee’s de facto adaptation does not always mean that the employee has consented to such changes. In the practice of the Court of Cassation, the typical situations in which implied consent is not accepted despite the employee’s de facto adaptation are substantial changes to the detriment of the employee in respect of wages and wage-related entitlements. Any adverse change in the employee’s wage or in wage-related entitlements directly or indirectly linked to the wage is excluded by the Court of Cassation from the scope of tacit acceptance. The Court of Cassation examines cases in which the employer “abuses the right to make substantial changes” by separating them into two groups, namely wage and other working conditions; the justification given is that changes to wages, one of the essential performances under the employment contract, may fundamentally upset the balance between the performances in the contract.[4] Within this approach, a unilateral change in wages is deemed to upset the fundamental balance of the contract and, therefore, the employee’s silence or continuation of work is not interpreted as consent.
As a natural consequence of this, an employee whose wage or wage-related entitlements have been reduced may, on the one hand, terminate the employment contract with just cause and, on the other hand, preserve the right to claim the monetary entitlements from which they have been deprived within the statutory limitation period. Indeed, according to the Court of Cassation, where the substantial change concerning wage reduction is not expressly accepted by the employee, the fact that a lower wage is paid during the payment period, or even that the payslip relating to such payment is signed by the employee, does not extinguish the employee’s right to claim the wage difference.[5]
This distinction, endorsed by the Court of Cassation, shows the following: Taking into account economic conditions and the difficulty of finding a new job, it is not realistic to expect employees to immediately resort to termination in the face of every change unilaterally implemented by the employer. Therefore, employees may opt to maintain the employment relationship for a certain period. However, such continuation does not result in any loss of rights, particularly in terms of wages and wage-related entitlements. Indeed, according to the Court of Cassation’s settled view, the employer may, in line with the economic requirements of the enterprise, propose a wage reduction and the employee may feel compelled to accept such proposal in order not to remain unemployed.[6] Nevertheless, in order for such change to be valid, it must strictly be implemented in accordance with the requirement of written form.
It should be emphasised that adverse changes in items of wage and wage-related entitlements are interpreted quite broadly by the Court of Cassation. Accordingly, not only direct and explicit changes in the base wage but also changes that may result in indirect economic loss for the employee can be considered substantial changes. For instance, a reduction in fuel entitlements despite no change in the daily visit schedule of a medical sales representative[7]; the assignment of the employee from a head office where transport by shuttle service is available to a branch where no such service exists, without providing a commuting allowance[8]; assignment of the employee from their existing position to a lower-level position or aggravation of working conditions[9] or reduction or complete elimination of any allowances paid at the workplace[10] may all constitute substantial changes. In such circumstances, the employee’s continuation of work without an explicit declaration of consent is likewise not treated as implied consent.
b. Cases Where the Employee’s Conduct Is Considered Implied Consent
From time to time, although certain changes made to working conditions are of a fundamental nature, the existence of implied consent is accepted in specific cases where the change has not been explicitly rejected. In other words, disputes arising out of such changes – and the related claims – are effectively deprived of legal protection in the eyes of the courts.
One such situation arises where the employee, without expressly rejecting the change of duty or the proposal for change, performs the requirements of the new job description uninterruptedly over a long period of time. According to the Court of Cassation, where this period of de facto adaptation reaches a level that “creates in the employer the belief that the change has been accepted,” the possibility of termination based on substantial change disappears. Although the case law of the Court of Cassation does not specify a fixed time limit for the “reasonable period” criterion, it may be said that periods of one year or more of de facto adaptation are likely to be assessed within this scope.[11], [12]
It must be stressed that, as noted above, where changes relate solely to the employee’s wage or wage-related entitlements, implied consent cannot be inferred. On the other hand, if an employee whose job description is changed and whose responsibilities are reduced in the new position, thereby leading to a lower wage, de facto adapts to this situation, the Court of Cassation may treat this as tacit acceptance.[13] In our view, the underlying assumption in this distinction is that an employee would not agree, without justification, to a wage reduction, but may implicitly accept such reduction in return for lower responsibilities or workload.
Another point to be highlighted concerns situations where the employee, despite not expressly accepting the change, signs other documents referring to such change. In such cases, the Court of Cassation may acknowledge the existence of indirect consent by reference and annex, and reject the employee’s claims based on substantial change on this ground.[14] Although these situations cannot be fully classified as implied consent, they may be described as “indirect consent” and form another focal point of debate concerning the application of the rules on substantial change.
The most important consequence of treating a particular conduct as implied consent concerns disputes between employer and employee. In assessing the lawfulness of an employee’s termination – and the consequent monetary claims brought before the courts – whether or not the employee consented to the conduct giving rise to termination is highly determinative. To illustrate this by way of an example where no working condition other than wage or wage-related entitlements has been changed: it is clear that an employee whose working conditions have been changed only in this respect cannot be deemed to have given implied consent to such change. Accordingly, such employee may not only terminate the employment contract with just cause but also claim the outstanding wage difference retrospectively. In fact, even if the employee signs payrolls indicating that a lower wage has been paid throughout the period during which the employment relationship continues, such signatures will not, in the eyes of the Court of Cassation, constitute acceptance.
Conversely, where an employee whose consent has not been obtained in accordance with legal requirements is assigned to a position requiring a narrower job description and less responsibility, and performs such position for a prolonged period, the existence of implied consent will now come into play. As a consequence, the employee’s decision to terminate will not be deemed justified. In addition, it is likely that such employee’s claims for outstanding wages will be rejected on the ground that “wages cannot be claimed for work that has not been performed”.
- Conclusion
Fundamental changes in working conditions may inevitably arise for employers in the context of organisational needs, efficiency targets and changing economic circumstances. However, Article 22 of Labour Act No. 4857 subjects the implementation of such changes to a clear procedure and is based on the principle of written form and foreseeability in employment relationships. In this framework, the requirements of written notification and written acceptance are not merely formal obligations; they also serve a protective function in preventing future disputes.
An examination of the case law of the Court of Cassation reveals that the employee’s de facto adaptation to the change is not in every case treated as implied consent; in particular, adverse changes to wages and wage-related entitlements may still be subject to dispute, even after being applied in practice for a long period. Conversely, in situations such as a change of duties that are not directly linked to the wage component, the employee’s long-term adaptation to the new situation, or the signing of other documents referring to changes that have not been expressly approved, may be regarded as implied consent, even where such changes concern wages.
Within this framework, the most critical aspect is to design the process correctly from the outset according to the nature of the planned change in working conditions. Changes implemented without obtaining written consent may appear to be applied without issue in the short term yet may become the subject of claims for outstanding wages, termination and compensation even after a long time. For this reason, managing processes of substantial change by jointly considering written notification, explicit consent and, where necessary, the option of valid termination is of paramount importance, both for managing legal risks and for ensuring the sustainability of employment relationships.
[1] Court of Cassation of the Republic of Türkiye, General Assembly of Civil Chambers, Case No. 2023/984 – Decision No. 2024/18, 17 April 2024.
[2] Court of Cassation of the Republic of Türkiye, 9th Civil Chamber, Case No. 2015/4786 – Decision No. 2015/12364, 30 March 2015.
[3] Court of Cassation of the Republic of Türkiye, General Assembly of Civil Chambers, Case No. 2023/186 – Decision No. 2023/240, 22 March 2023
[4] Court of Cassation of the Republic of Türkiye, 9th Civil Chamber, Case No. 2024/907 – Decision No. 2024/4874,14 March 2024
[5] Court of Cassation of the Republic of Türkiye, 9th Civil Chamber, Case No. 2020/6849 – Decision No. 2021/4195, 17 February 2021; Court of Cassation of the Republic of Türkiye, 9th Civil Chamber, Case No. 2024/907 – Decision No. 2024/4874, 14 March 2024
[6] Court of Cassation of the Republic of Türkiye, General Assembly of Civil Chambers, Case No. 2016/1633 – Decision No. 2017/1176, 14 July 2017
[7] Court of Cassation of the Republic of Türkiye, 9th Civil Chamber, Case No. 2015/13462 – Decision No. 2017/15484, 11 October 2017
[8] Court of Cassation of the Republic of Türkiye, 9th Civil Chamber, Case No. 2016/18207 – Decision No. 2020/6369, 24 July 2020
[9] For several sample judgments reflecting well-established case law, see: Court of Cassation of the Republic of Türkiye, 9th Civil Chamber, Case No. 2023/20267 – Decision No. 2024/2137, 14 February 2024; Case No. 2021/4643 – Decision No. 2021/8989, 17 May 2024; Case No. 2020/6849 – Decision No. 2021/4195, 17 February 2021
[10] Court of Cassation of the Republic of Türkiye, 9th Civil Chamber, Case No. 2019/7770 – Decision No. 2019/22461, 16 December 2019
[11] Court of Cassation of the Republic of Türkiye, 9th Civil Chamber, Case No. 2025/733 – Decision No. 2025/3710, 22 April 2025; Court of Cassation of the Republic of Türkiye, 9th Civil Chamber, Case No. 2025/141 – Decision No. 2025/5487, 26 June 2025; Court of Cassation of the Republic of Türkiye, 9th Civil Chamber, Case No. 2025/823 – Decision No. 2025/3402, 14 April 2025; Court of Cassation of the Republic of Türkiye, 9th Civil Chamber, Case No. 2023/494 – Decision No. 2023/1658, 8 February 2023; Court of Cassation of the Republic of Türkiye, 9th Civil Chamber, Case No. 2022/11071 – Decision No. 2022/13684, 31 October 2022
[12] In a series of disputes examined before the 9th Civil Chamber of the Court of Cassation, a group of employees terminated their employment contracts on the grounds that the notification of change of duty dated 03.01.2022 constituted a fundamental modification of working conditions. The Court of Cassation overturned the first-instance court’s decision in favour of the employees, holding that their de facto adaptation with the change had continued for a period that could not be regarded as reasonable from the date they were notified. Although the action before the first-instance court bore a 2023 merits number, the dates of termination and of filing were not indicated in the judgment. Nevertheless, it is understood that the claimants continued working for more than one year following the disputed change. (See Court of Cassation of the Republic of Türkiye, 9th Civil Chamber, Case No. 2025/198 – Decision No. 2025/2226, 03 March 2025)
[13] Court of Cassation of the Republic of Türkiye, 9th Civil Chamber, Case No. 2021/12740 – Decision No. 2022/1024, 25 January 2022; Court of Cassation of the Republic of Türkiye, 9th Civil Chamber, Case No. 2023/494 – Decision No. 2023/1658, 8 February 2023; Court of Cassation of the Republic of Türkiye, 9th Civil Chamber, Case No. 2024/7205 – Decision No. 2024/9498, 10 June 2024
[14] Court of Cassation of the Republic of Türkiye, 9th Civil Chamber, Case No. 2016/9412 – Decision No. 2019/16512, 23 September 2019; Court of Cassation of the Republic of Türkiye, General Assembly of Civil Chambers, Case No. 2022/536 – Decision No. 2023/194, 15 March 2023
