All parties to any proceeding before the board in which any rate decision has been rendered or made pursuant to Kan. Stat. Ann. § 13-1228a within 30 days prior to July 1, 1982, in which no action has been commenced to set aside or vacate such order, may, before July 11, 1982, apply for rehearing in respect to any matter determined therein, and thereafter all proceedings shall be in accordance with the provisions of this act.