Michigan Compiled Laws, Chapter 565. Conveyances of Real Property § 565.17

Sec. 17. At the time mentioned in the summons, or at any time to which the hearing may be adjourned, the due execution of the deed may be proved by the testimony of 1 or more of the subscribing witnesses; and if proved to the satisfaction of the court, it shall certify the same, and in the certificate he or she shall note the presence or absence of the grantor, as the fact may be.