215 ILCS 5/35B-20

(a) A domestic stock company shall not file a plan of division with the Director unless the plan of division has been approved in accordance with: (1) any applicable provisions of its articles of incorporation and bylaws; and (2) all laws of this State governing the internal affairs of a domestic stock company that provide for approval of a merger. (b) If any provision of the articles of incorporation or bylaws of a domestic stock company requires that a specific number or percentage of board of directors or shareholders approve the proposal or adoption of a plan of merger, or imposes other special procedures for the proposal or adoption of a plan of merger, such domestic stock company shall adhere to such provision in proposing or adopting a plan of division. If any provision of the articles of incorporation or bylaws of a domestic stock company is amended, such amendment shall thereafter apply to a division only in accordance with its express terms.