California Code, Government Code - GOV § 17559

(a) The commission may order a reconsideration of all or part of a test claim or incorrect reduction claim on petition of any party. The power to order a reconsideration or amend a test claim decision shall expire 30 days after the statement of decision is delivered or mailed to the claimant. If additional time is needed to evaluate a petition for reconsideration filed prior to the expiration of the 30-day period, the commission may grant a stay of that expiration for no more than 30 days, solely for the purpose of considering the petition. If no action is taken on a petition within the time allowed for ordering reconsideration, the petition shall be deemed denied.

(b) A claimant or the state may commence a proceeding in accordance with the provisions of Section 1094.5 of the Code of Civil Procedure to set aside a decision of the commission on the ground that the commission's decision is not supported by substantial evidence. The court may order the commission to hold another hearing regarding the claim and may direct the commission on what basis the claim is to receive a rehearing.