5 CFR § 353.106 - Personnel actions during employee's absence.
(a) An employee absent because of service in the uniformed services is to be carried on leave without pay unless the employee elects to use other leave or freely and knowingly provides written notice of intent not to return to a position of employment with the agency, in which case the employee can be separated. (Note: A separation under this provision affects only the employee's seniority while gone; it does not affect his or her restoration rights.)
(c) Agency promotion plans must provide a mechanism by which employees who are absent because of compensable injury or uniformed service can be considered for promotion. In addition, agencies have an obligation to consider employees absent on military duty for any incident or advantage of employment that they may have been entitled to had they not been absent. This is determined by:
(1) Considering whether the “incident or advantage” is one generally granted to all employees in that workplace and whether it was denied solely because of absence for military service;
(2) Considering whether the person absent on military duty was treated the same as if the person had remained at work; and
(3) Considering whether it was reasonably certain that the benefit would have accrued to the employee but for the absence for military service.