Gov. Code, § 71658

(a) Except as provided in subdivision (b), the implementation date of this article is the effective date of this chapter.

(b) Representatives of a trial court and representatives of recognized employee organizations may mutually agree to an implementation date of this article different from that specified in subdivision (a). However, if any provisions of this chapter are governed by an existing memorandum of understanding or agreement covering trial court employees, as to those provisions, the implementation date shall be either the date a successor memorandum of understanding or agreement is effective or, if no agreement for a successor memorandum of understanding or agreement is reached, 90 days from the date of the expiration of the predecessor memorandum of understanding or agreement unless representatives of the trial court and representatives of recognized employee organizations mutually agree otherwise.