Cal. CCP § 1054

(a) When an act to be done, as provided in this code, relates to the pleadings in the action, or the preparation of bills of exceptions, or of amendments thereto, or to the service of notices other than of appeal and of intention to move for a new trial, the time allowed therefor, unless otherwise expressly provided, may be extended, upon good cause shown, by the judge of the court in which the action is pending, or by the judge who presided at the trial of the action; but the extension so allowed shall not exceed 30 days, without the consent of the adverse party.

(b) In all cases in which the court or judge is authorized by this section to grant an extension of time, the extension of time shall be granted when all attorneys of record of parties who have appeared in the action agree in writing to the extension of time, and any extension of time previously granted by stipulation of all attorneys of record of parties who have appeared in the action shall not be included in the computation of the 30-day limitation upon extensions of time allowed by the court or judge.