Mich. Comp. Laws § 168.175: State senator or representative; resignation, notice; effective for duration of unexpired legislative term.

Sec. 175.

An individual elected to the office of state senator or representative who desires to resign shall file a written notice containing the effective date of the resignation with the presiding officer of his or her respective house, who shall immediately transmit the written notice to the governor. The resignation of an individual from the office of state senator or representative remains in effect for the duration of the unexpired legislative term.