Cal. Civ. Proc. Code § 1282.4
(b) Notwithstanding any other law, including Section 6125 of the Business and Professions Code, an attorney admitted to the bar of any other state may represent the parties in the course of, or in connection with, an arbitration proceeding in this state, provided that the attorney, if not admitted to the State Bar of California, satisfies all of the following:
(c) Within a reasonable period of time after the attorney described in subdivision (b) indicates an intention to appear in the arbitration, the attorney shall serve a certificate in a form prescribed by the State Bar of California on the arbitrator, arbitrators, or arbitral forum, the State Bar of California, and all other parties and counsel in the arbitration whose addresses are known to the attorney. The certificate shall state all of the following:
(j)