5 CFR §831.1713

1. (a)To elect to enter phased retirement status, a retirement-eligible employee covered by § 831.1711 must—
   1. (1)Submit to an authorized agency official a written and signed request to enter phased employment, on a form prescribed by OPM;
   2. (2)Obtain the signed written approval of an authorized agency official to enter phased employment; and
   3. (3)File an application for phased retirement, in accordance with § 831.104.
2. (b)Except as provided in paragraph (c) of this section, an applicant for phased retirement may withdraw his or her application any time before the election becomes effective, but not thereafter.
3. (c)An applicant for phased retirement may not withdraw his or her application after OPM has received a certified copy of a court order (under part 581 or part 838 of this chapter) affecting the benefits.
4. (d)
   1. (1)An employee and an agency approving official may agree to a time limit to the employee's period of phased employment as a condition of approval of the employee's request to enter phased employment and phased retirement, or by mutual agreement after the employee enters phased employment status.
   2. (2)To enter into such an agreement, the employee and the approving official must complete a written and signed agreement.
   3. (3)The written agreement must include the following:
      1. (i)The date the employee's period of phased employment will terminate;
      2. (ii)A statement that the employee can request the approving official's permission to return to regular employment status at any time as provided in § 831.1721; the agreement must also explain how returning to regular employment status would affect the employee, as described in §§ 831.1721-1723.
      3. (iii)A statement that the employee has a right to elect to fully retire at any time as provided in § 831.1731;
      4. (iv)A statement that the employee may accept a new appointment at another agency, with or without the new agency's approval of phased employment, at any time before the expiration of the agreement or within 3 days of the expiration of the agreement; the agreement must also explain how accepting an appointment at a new agency as a regular employee would affect the employee, as described in §§ 831.1721-1723;
      5. (v)An explanation that when the agreed term of phased employment ends, the employee will be separated from employment and that such separation will be considered voluntary based on the written agreement; and
      6. (vi)An explanation that if the employee is separated from phased employment and is not employed within 3 days (i.e., the employee has a break in service of greater than 3 days), the employee will be deemed to have elected full retirement.
   4. (4)The agency approving official and the employee may rescind an existing agreement, or enter into a new agreement to extend or reduce the term of phased employment agreed to in an existing agreement, by entering into a new written agreement meeting the requirements of this paragraph, before the expiration of the agreement currently in effect.
5. (e)An agency must establish written criteria that will be used to approve or deny applications for phased retirement before approving or denying applications for phased retirement.