If a certificate of completion for a change of organization or reorganization has not been filed within one year after the commission approves a proposal for that proceeding, the proceeding shall be deemed terminated unless prior to the expiration of that year the commission authorizes an extension of time for that completion. The extension may be for any period deemed reasonable to the commission for completion of necessary prerequisite actions by any party. If a proceeding has not been completed because of the order or decree of a court of competent jurisdiction temporarily enjoining or restraining the proceedings, this shall not be deemed a failure of completion and the one-year period shall be tolled for the time that order or decree is in
effect.