Me. Rev. Stat. tit. 34-A, § 5809

Whenever it appears to the board that a person on parole is no longer in need of supervision, it may order the warden of the institution from which the parolee was released to issue the parolee a certificate of discharge, except in the case of persons serving a life sentence who may not be discharged from parole in less than 10 years after release on parole.