Ohio Rev. Code Ann. § 1701.79
(B) The agreement of merger or consolidation shall set forth the following:
(E) At any time prior to filing the certificate of merger or consolidation, the merger or consolidation may be abandoned by the directors of any of the constituent corporations if the directors are authorized to do so by the agreement of merger or consolidation. The agreement may contain a provision authorizing the directors of the constituent corporations to amend the agreement at any time prior to the filing of the certificate of merger or consolidation, except that, after the adoption of the agreement by the shareholders of any domestic constituent corporation, the directors shall not be authorized to amend the agreement to do any of the following: