Irrevocability of an election of FERS coverage
Primary source
Verbatim text below is from the Electronic Code of Federal Regulations (eCFR), a public-domain U.S. government work. Always verify the current version with the eCFR before relying on it for any legal matter.
Full Text
(a) An election to be covered by FERS becomes irrevocable on the date it becomes effective.
(b) If, during the 1998 open enrollment period, an employee files an election on an SF 3109 to remain covered by CSRS, the employee may revoke such an election by filing another election during the 1998 open enrollment period.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.