Each domestic limited liability company that is a party to a merger shall approve the plan of merger, unless the articles of organization or a written operating agreement of the limited liability company provides otherwise, by the unanimous vote of the members of the limited liability company. However, a provision of a limited liability company’s articles of organization or operating agreement purporting to authorize the limited liability company to approve a merger by a less than unanimous vote of the members shall be effective to permit approval of a merger by a less than unanimous vote only if either (i) the articles of organization or operating agreement included that provision at the time each member who does not vote in favor of the merger became bound by the articles of organization or operating agreement or (ii) the provision was added to the articles of organization or operating agreement through an amendment to which each member who does not vote in favor of the merger specifically consented.