Mich. Comp. Laws § 168.322a

Sec. 322a. After the filing of a nominating petition or filing fees by or in behalf of a proposed candidate for a city office, the candidate shall not be permitted to withdraw unless a written notice of withdrawal is served on the city clerk not later than 4 o'clock, eastern standard time, in the afternoon of the third day after the last day for filing the petition or filing fee as provided in this act or in local charters unless the third day falls on a Saturday, Sunday or legal holiday, in which case the withdrawal may be served on the city clerk up to 4 o'clock, eastern standard time, on the next secular day.