In the absence of the agreement mentioned inarticle L. 3142-129, the employee informs the employer by any means giving a date certain of his intention to continue or to terminate his employment contract at the end of his leave or his period of part-time work, three months before its end when the duration of the leave or the period of part-time work is six months or more and at least two months before its end when this duration is less than six months.