Mich. Comp. Laws § 450.4706

Sec. 706. (1) Unless a plan of merger provides otherwise, at any time before the effective date of a certificate of merger, the merger may be abandoned in accordance with the procedure set forth in the plan of merger or, if no procedure to abandon the merger is set forth in the plan of merger, by the unanimous vote of the members entitled to vote in each domestic limited liability company that is a constituent entity, unless an operating agreement of a domestic limited liability company provides otherwise. (2) If a certificate of merger has been filed by a constituent domestic limited liability company, it shall file a certificate of abandonment within 10 days after the abandonment but not later than the effective date of the certificate of merger.