Can an employer agree with an employee that he or she will retire at a particular age?
Although an employer cannot dismiss an employee on grounds of retirement (unless this is objectively justified), it is not unlawful for it to agree that he or she will retire at a particular age if the employee wishes to do so. The employee is essentially resigning by reason of his or her wish to retire. A retirement will be lawful if it is the employee's decision and no pressure has been placed on him or her to retire.
However, if the employee changes his or her mind about retiring at a particular age, before giving notice of the resignation, the employer will not be able to enforce the agreement and insist that the employee retire.