Michigan Compiled Laws, Chapter 450. Corporations § 450.1455

Sec. 455. With respect to an action to be taken by the shareholders, if the articles of incorporation require the vote or concurrence of the holders of a greater proportion of the shares, or of a class or series of shares, than required by this act with respect to the action, the articles shall control. An amendment of the articles which changes or deletes such a provision shall be authorized by the vote required to amend the articles pursuant to section 611,  1 or by the same vote as would be required to take action under the provision, whichever is greater. The failure to include a provision of the kind described in this section in the articles shall not invalidate any bylaw or agreement which would otherwise be considered valid.