California Code, Probate Code - PROB § 8422

(a) The testator may by will confer on a person the power to designate an executor or coexecutor, or successor executor or coexecutor. The will may provide that the persons so designated may serve without bond.

(b) A designation shall be in writing and filed with the court. Unless the will provides otherwise, if there are two or more holders of the power to designate, the designation shall be unanimous, unless one of the holders of the power is unable or unwilling to act, in which case the remaining holder or holders may exercise the power.

(c) Except as provided in this section, an executor does not have authority to name a coexecutor, or a successor executor or coexecutor.