Wis. Stat. § 185.51: Amendments to articles.

(1) At any member meeting a cooperative may adopt any amendment to its articles which is lawful under s. 185.05, if a statement of the nature of the amendment was contained in the notice of the meeting.

(2) Unless stockholders are entitled by s. 185.52 to vote on an amendment, an amendment is adopted when approved by two-thirds of the member votes cast thereon.