Any certificated employee of a district having an annuity reserve fund may enter into an amendment of his or her employment contract for the purpose of effecting a reduction in salary. The reduction shall be deposited by the employer, at the employee’s request, in the district’s annuity reserve fund. The deposits shall be used to provide the employee an annuity within the meaning of Section 403(b) of the Internal Revenue Code of 1986 (26 U.S.C.A. Sec. 403(b)).