Michigan Compiled Laws, Chapter 38. Civil Service and Retirement § 38.1434

Sec. 134. A qualified participant or former qualified participant may nominate 1 or more individuals as a refund beneficiary by filing written notice of nomination with the department. If the qualified participant or former qualified participant is married at the time of the nomination and the participant's spouse is not the refund beneficiary for 100% of the account, the nomination is not effective unless the nomination is signed by the participant's spouse if the signature of the participant's spouse is required by the plan document. However, the department may waive this requirement if the spouse's signature cannot be obtained because of extenuating circumstances.