Mich. Comp. Laws § 700.3702: Priority among different letters.

Sec. 3702.

A person to whom general letters are issued first has exclusive authority under the letters until the appointment is terminated or modified. If, through error, general letters are afterwards issued to another person, the first appointed representative may recover estate property in the hands of the representative subsequently appointed, but the acts of the latter done in good faith before notice of the first letters are not void for want of validity of appointment.