In Claypool v. Wilson (1992) 4 Cal.App.4th 646, the court considered a challenge to a state law repealing a supplemental cost of living adjustment available to retired state employees and replacing it with a new supplemental cost of living adjustment. (Id. at pp. 652-659.) With respect to employees who had retired before the former supplemental COLAs went into effect, the court found no vested contractual rights were at issue. "The contractual basis of a pension right is the exchange of an employee's services for the pension right offered by the statute. . A member whose employment terminated before enactment of a statute offering additional benefits does not exchange services for the right to the benefits." (Id. at p. 662.)