(a) When a beneficiary resumes service, as defined in subdivision 455(a)(21) of this title, he or she shall again become a member of the System, shall contribute at the rate established for members of his or her group, and shall not be entitled to receive a retirement allowance.

(b) Upon the subsequent retirement of an employee who once again became a member under subsection (a) of this section, the employee shall once again become a beneficiary whose former retirement allowance shall be restored under the same plan provisions applicable at the time of the initial retirement, but the beneficiary shall not be entitled to cost of living adjustments for the period during which he or she was restored to service. In addition to the former retirement allowance, a beneficiary shall be entitled to a retirement allowance separately computed for the period beginning with his or her last restoration to service for which the member has made a contribution. If the beneficiary is not vested in the system since he or she was last restored to service, the member's contributions plus accumulated interest shall be returned to him or her. (Added 2009, No. 24, § 1.)