Michigan Compiled Laws, Chapter 700. Estates and Protected Individuals Code § 700.2905

(a) A disclaimer by an appointee must be delivered to the donee, to the personal representative of the donee's estate, or to the fiduciary under the instrument that created the power of appointment. The disclaimer by the appointee must be delivered after the exercise of the power of appointment by the donee and before any event described in section 2910.  1

(b) A disclaimer by a taker in default must be delivered to the donee, to the fiduciary under the instrument that created the power of appointment, or to 1 of the persons entitled to the property in the event of a disclaimer. The disclaimer by a taker in default may be delivered before or after the lapse or release of the power of appointment, and must be delivered before any event described in section 2910.

(a) If the fiduciary is a personal representative, to all the devisees under the will who are then living and whose whereabouts are known or reasonably ascertainable.

(b) If the fiduciary is a trustee, to another incumbent trustee who has not disclaimed the power or to all the beneficiaries of the trust who are then living and whose whereabouts are known or reasonably ascertainable.

(c) If the fiduciary is a guardian or conservator, to the interested persons.

(d) If the fiduciary is an agent, to the principal or, if the principal is legally incapacitated, to the principal's presumptive heirs at law.