Cal. R. 3.770
A dismissal of an entire class action, or of any party or cause of action in a class action, requires court approval. The court may not grant a request to dismiss a class 23 action if the court has entered judgment following final approval of a settlement. Requests for dismissal must be accompanied by a declaration setting forth the facts on which the party relies. The declaration must clearly state whether consideration, direct or indirect, is being given for the dismissal and must describe the consideration in detail.
The court may grant the request without a hearing. If the request is disapproved, notice of tentative disapproval must be sent to the attorneys of record, Any party may seek, within 15 calendar days of the service of the notice of tentative disapproval, a hearing on the request. If no hearing is sought within that period, the request for dismissal will be deemed denied.
If the court has certified the class, and notice of the pendency of the action has been provided to class members, notice of the dismissal must be given to the class in the manner specified by the court. If the court has not ruled on class certification, or if notice of the pendency of the action has not been provided to class members in a case in which such notice was required, notice of the proposed dismissal may be given in the manner and to those class members specified by the court, or the action may be dismissed without notice to the class members if the court finds that the dismissal will not prejudice them.
Cal. R. Ct. 3.770