Ius variandi is the power that the employer has to unilaterally alter non-essential conditions of the individual employment contract, leaving out of that power, among others:.

This power is considered to derive from the employer's right to organize and direct the work of his dependents. The limit to the application of ius variandi is a triple filter framed by its reasonableness "Principle of reasonableness (Labor Law)") (that is not arbitrary), functionality (that obeys an understandable reason), and indemnity of the worker (that it does not cause patrimonial or moral impairment, or that it causes material damage that is adequately compensated).

Some legislation distinguishes the situation of the worker according to whether he or she has an absolute or relative inability to accept the change in working conditions. The impossibility is absolute when due to the nature, severity or extent of the damages caused, you cannot be forced to accept it (for example, a change in schedule or place of work that would prevent you from continuing the studies you are carrying out). The impossibility is relative when the employer can compensate for the harm caused (for example, paying a higher cost of transportation from home to work caused by the change of workplace), in which case the worker must accept the change if the employer agrees to compensate him for the harm.

The art. 66 of the Employment Contract Regime (according to Law 26,088) provides that "The employer is authorized to introduce all those changes related to the form and modalities of the provision of work, as long as these changes do not involve an unreasonable exercise of that power, nor do they alter essential modalities of the contract, nor do they cause material or moral damage to the worker. When the employer provides for measures prohibited by this article, the worker will have the possibility of choosing to consider himself dismissed without cause or take action seeking the reestablishment of the altered conditions. In this last case, the action will be substantiated by the summary procedure, and innovation cannot be made in the conditions and modalities of work, unless these are general for the establishment or section, until a final ruling is issued.