An employment contract may be subject to change. Depending on the type of changes envisaged by the employer, the employee’s agreement will be required.   A change in remuneration can only be made with the employee’s agreement, and the employee is free to refuse and has one month from receipt of the registered letter with acknowledgement of receipt to make his decision. Silence does not mean acceptance and an employee can always take action, if necessary, by bringing a case before the Conseil des Prud’hommes, even after the changes have been made.