Mich. Comp. Laws § 168.74

Sec. 74. A person who has been certified by the state central committee of any party as nominated for the office of lieutenant governor, secretary of state, or attorney general may withdraw by filing a written notice of withdrawal with the secretary of state or his or her authorized agent and a copy with the chairperson and the secretary of the state central committee of the party not later than 4 p.m., eastern standard time, of the fourth business day following the conclusion of the convention at which the person was nominated.