Cal. Health & Safety Code § 110135

Before any alleged violation of this part is reported to the Attorney General, a district attorney, or a city attorney for the institution of a criminal proceeding, the person against whom this proceeding is contemplated may be given appropriate notice and an opportunity to show cause why he or she should not be prosecuted and to present additional facts that may mitigate the action. The showing may be presented either orally or in writing, in person, or by attorney.