term:

Functus Officio

functus officio adj

[Latin, having performed his duty, having served its purpose]
: of no further official authority or legal effect [the warrant… had been returned and was functus officio "Cady v. Dombrowski, 413 U.S. 433 (1973)"] [once an arbitrator makes an award she is functus officio] used esp. of an officer who is no longer in office or of an instrument that has fulfilled its purpose

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.