At any time before the effective date of the certificate of merger, subject to any contractual rights, a corporation may abandon a merger without further shareholder or member action, under a procedure set forth in the plan of merger or, if the plan of merger does not include an abandonment procedure, in the manner determined by the board. If a certificate of merger was filed by a corporation that abandons a merger, it shall file a certificate of abandonment within 10 days after the abandonment, but not later than the proposed effective date.