California Code, Education Code - EDC § 26000.5

An employer whose governing board has elected to provide the benefits of this part for its employees pursuant to Section 26000 shall enter into an agreement with the State Teachers' Retirement System.  The agreement shall specify the terms and conditions of the employer's formal action to provide the Cash Balance Benefit Program and shall remain in effect unless or until the employer exercises the right to discontinue the program pursuant to Chapter 17 (commencing with Section 28100).