Election requirements
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 employee who completed a qualifying move under § 847.402(b) may elect to be covered by a NAFI retirement system for all Federal service following the qualifying move.
(b) A survivor eligible for benefits under FERS may make an election under this section if the employee was otherwise eligible to make an election, but died before expiration of the time limit under § 847.304.
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.