(1)    Authorization and execution. Except as otherwise provided in this subsection, any person who has entered into a contribution agreement under s. 193.711 or an agreement to purchase cooperative securities, or any member, may enter into a written agreement with the cooperative that relates to the control of or the liquidation, dissolution, or termination of the cooperative, or any phase of the business and affairs of the cooperative. Such an agreement may not take effect unless signed by all persons who are then members and all persons who have entered into contribution agreements. An agreement under this subsection may not relate to patron member voting control under s. 193.545 or patron member allocation and distribution provisions under s. 193.721.

   (2)   Same effect as articles and bylaws. Wherever this chapter provides that a particular result may or shall be obtained through a provision in the articles or bylaws, the same result may be accomplished through a provision in an agreement under sub. (1) or a procedure established in such an agreement.

   (3)   Other agreements not affected. This section does not limit the authority of persons to enter into agreements otherwise valid, nor is the procedure set forth in this section the exclusive method of agreement among members or between the members and the cooperative with respect to any of the matters described.