Mich. Comp. Laws § 700.3717
If 2 or more persons are appointed personal corepresentatives and unless the will provides otherwise, the concurrence of all is required on an act connected with the estate's administration or distribution. This restriction does not apply if a personal corepresentative receives and gives a receipt for property due the estate, if the concurrence of all cannot readily be obtained in the time reasonably available for emergency action necessary to preserve the estate, or if a personal corepresentative has been delegated to act for the other. If actually unaware that another also has been appointed to serve or if advised by the personal representative with whom the person deals that 1 personal representative alone has authority to act for a reason mentioned in this section, a person dealing with a personal corepresentative is as fully protected as if the personal corepresentative with whom the person deals is the sole personal representative.
MCL 700.3717