5 CFR 837.801 - Unperfected entitlement to CSRS benefits based on a prior separation.
(a) An employee who meets the age and service requirements for title to a non-disability annuity under CSRS on the basis of a prior separation, but did not apply for that annuity before a subsequent separation from service to which a different annuity entitlement attaches, may elect, on application, to receive either -
(1) The annuity based on the later separation; or
(2) The annuity based on the prior separation, with payment of annuity suspended during the period(s) of employment subsequent to the commencing date of annuity, and such benefits as would be payable had the subsequent period(s) of employment been performed under the provisions of this part.
(b) When an individual who has applied for a deferred annuity under CSRS is reemployed under CSRS before the commencing date of that annuity, the application is deemed to have not been made.