Michigan Compiled Laws, Chapter 450. Corporations § 450.1615

Sec. 615. (1) The holders of the outstanding shares of a class may vote as a class upon a proposed amendment, whether or not entitled to vote thereon by the articles of incorporation, if the amendment would increase or decrease the aggregate number of authorized shares of the class, or alter or change the powers, preferences or special rights of the shares of the class or other classes so as to affect the class adversely.

(2) If a proposed amendment would alter or change the powers, preferences or special rights of a class so as to affect adversely 1 or more series of a class, but not the entire class, then only the shares of the 1 or more series affected by the amendment shall as a group be considered a single class for the purposes of this section.