Wis. Stat. § 204.104: Election of an existing business corporation to become a benefit corporation.

(1) Amendment. An existing business corporation may become a benefit corporation under this chapter by amending its articles so that they contain, in addition to the requirements of s. 180.0202, a statement that the corporation is a benefit corporation.

(2) Fundamental transactions. If a corporation that is not a benefit corporation is a party to a merger, consolidation, or division or is the exchanging corporation in an interest exchange, and the surviving, new, or any resulting corporation in the merger, consolidation, division, or interest exchange is to be a benefit corporation, then the plan of merger, consolidation, division, or interest exchange shall not be effective unless the articles of the surviving, new, or resulting corporation contain a statement that the corporation is a benefit corporation.

(3) Shareholder vote. Notwithstanding any provision to the contrary in the corporation’s articles of incorporation, bylaws, or shareholder agreements, the amendment of a corporation’s articles or its entry into a fundamental transaction under this chapter requires approval by the affirmative vote of the holders of at least two-thirds of the shares entitled to vote on the matter. If the amendment or fundamental transaction is approved, a shareholder who did not vote in favor of the amendment or fundamental transaction is entitled to assert dissenters’ rights under ss. 180.1301 to 180.1331.