California Code, Business and Professions Code - BPC § 19517

(a) The board, upon due consideration, may overrule any steward's decision other than a decision to disqualify a horse due to a foul or a riding or a driving infraction in a race, if a preponderance of the evidence indicates any of the following:

(b) However, any decision pertaining to the finish of a race, as used for purposes of parimutuel fund distribution to winning ticketholders, may not be overruled.  Furthermore, any decision pertaining to the distribution of purses may be changed only if a claim is made in writing to the board by one of the involved owners or trainers, and a preponderance of the evidence clearly indicates to the board that one or more of the grounds for protest, as outlined in regulations adopted by the board, has been substantiated.  The chairperson of the board may issue a stay of execution pending appeal from a steward's decision if the facts justify the action.