Mich. Comp. Laws § 168.194

Sec. 194. After the filing of a nominating petition or filing fee by or in behalf of a proposed candidate for any of the offices named in section 191 of this act, such candidate shall not be permitted to withdraw unless a written notice of withdrawal is served on the county clerk or his duly authorized agent not later than 4 o'clock, eastern standard time, in the afternoon of the third day after the last day for filing such petition or filing fee, as in this act provided, unless the third day falls on a Saturday, Sunday or legal holiday, in which case the notice of withdrawal may be served on the clerk up to 4 o'clock, eastern standard time, on the next secular day.