California Code, Labor Code - LAB § 5906

Upon the filing of a petition for reconsideration, or having granted reconsideration upon its own motion, the appeals board may, with or without further proceedings and with or without notice affirm, rescind, alter, or amend the order, decision, or award made and filed by the appeals board or the workers' compensation judge on the basis of the evidence previously submitted in the case, or may grant reconsideration and direct the taking of additional evidence. Notice of the time and place of any hearing on reconsideration shall be given to the petitioner and adverse parties and to other persons as the appeals board orders.