29 CFR § 825.219 - Rights of a key employee.
(a) An employer who believes that reinstatement may be denied to a key employee, must give written notice to the employee at the time the employee gives notice of the need for FMLA leave (or when FMLA leave commences, if earlier) that he or she qualifies as a key employee. At the same time, the employer must also fully inform the employee of the potential consequences with respect to reinstatement and maintenance of health benefits if the employer should determine that substantial and grievous economic injury to the employer's operations will result if the employee is reinstated from FMLA leave. If such notice cannot be given immediately because of the need to determine whether the employee is a key employee, it shall be given as soon as practicable after being notified of a need for leave (or the commencement of leave, if earlier). It is expected that in most circumstances there will be no desire that an employee be denied restoration after FMLA leave and, therefore, there would be no need to provide such notice. However, an employer who fails to provide such timely notice will lose its right to deny restoration even if substantial and grievous economic injury will result from reinstatement.
(b) As soon as an employer makes a good faith determination, based on the facts available, that substantial and grievous economic injury to its operations will result if a key employee who has given notice of the need for FMLA leave or is using FMLA leave is reinstated, the employer shall notify the employee in writing of its determination, that it cannot deny FMLA leave, and that it intends to deny restoration to employment on completion of the FMLA leave. It is anticipated that an employer will ordinarily be able to give such notice prior to the employee starting leave. The employer must serve this notice either in person or by certified mail. This notice must explain the basis for the employer's finding that substantial and grievous economic injury will result, and, if leave has commenced, must provide the employee a reasonable time in which to return to work, taking into account the circumstances, such as the length of the leave and the urgency of the need for the employee to return.
(c) If an employee on leave does not return to work in response to the employer's notification of intent to deny restoration, the employee continues to be entitled to maintenance of health benefits and the employer may not recover its cost of health benefit premiums. A key employee's rights under FMLA continue unless and until the employee either gives notice that he or she no longer wishes to return to work, or the employer actually denies reinstatement at the conclusion of the leave period.
(d) After notice to an employee has been given that substantial and grievous economic injury will result if the employee is reinstated to employment, an employee is still entitled to request reinstatement at the end of the leave period even if the employee did not return to work in response to the employer's notice. The employer must then again determine whether there will be substantial and grievous economic injury from reinstatement, based on the facts at that time. If it is determined that substantial and grievous economic injury will result, the employer shall notify the employee in writing (in person or by certified mail) of the denial of restoration.