Mich. Comp. Laws § 450.156

Sec. 156. Same; amendment of trust agreement. If the donor or grantor in any such trust instrument, shall desire to alter, amend, enlarge or restrict the gift or grant or any of the terms or conditions thereof, and does so, it shall be the duty of such trustees to forthwith file a verified copy of such amended trust instrument in the same manner as provided for original articles, and any amendments to such articles occasioned by such amended trust instrument shall likewise be forthwith made and so filed by such trustees, but no such amendments to the articles shall be valid that change the original purposes of the corporation in their entirety.