Wash. Rev. Code § 10.01.120
Whenever a prisoner has been sentenced to death, the governor shall have power to commute such sentence to imprisonment for life at hard labor; and in all cases in which the governor is authorized to grant pardons or commute sentence of death, he or she may, upon the petition of the person convicted, commute a sentence or grant a pardon, upon such conditions, and with such restrictions, and under such limitations as he or she may think proper; and he or she may issue his or her warrant to all proper officers to carry into effect such pardon or commutation, which warrant shall be obeyed and executed, instead of the sentence, if any, which was originally given. The governor may also, on good cause shown, grant respites or reprieves from time to time as he or she may think proper.
RCW 10.01.120
Governor's powers: State Constitution Art. 3 ss 9, 11.
Record of pardons, etc., governor to keep: RCW 43.06.020.