(a) Not later than the 20th day after the date the party or the party's representative receives notice of the commissioner's decision under Section 21.304, the party may file a request for rehearing.
(b) A request for rehearing is not required for a party to appeal the commissioner's decision under Section 21.307.
(c) A request for rehearing is denied by operation of law if the commissioner does not issue an order before the 45th day after the date the party or the party's representative receives notice of the commissioner's decision.