Me. Rev. Stat. tit. 15, § 2163

In any case in which the Governor is authorized by the Constitution to grant a pardon, the Governor may, upon petition of the person convicted, grant it upon such conditions and with such restrictions and under such limitations as the Governor considers proper, and the Governor may issue the Governor's warrant to all proper officers to carry the pardon into effect; the warrant must be obeyed and executed instead of the sentence originally awarded.