Michigan Compiled Laws, Chapter 600. Revised Judicature Act of 1961 § 600.2161

Sec. 2161. In any suit or proceeding in any court in this state, either party, if he shall call as a witness in his behalf, the opposite party, employee or agent of said opposite party, or any person who at the time of the happening of the transaction out of which such suit or proceeding grew, was an employee or agent of the opposite party, shall have the right to cross-examine such witness the same as if he were called by the opposite party; and the answers of such witness shall not interfere with the right of such party to introduce evidence upon any issue involved in such suit or proceeding, and the party so calling and examining such witness shall not be bound to accept such answers as true.