19-1-824. Federal-state agreement. On certification, the governor shall direct the department director to enter into a modification to the existing agreement with the appropriate officers of the federal government, pursuant to section 218 of the Social Security Act, 42 U.S.C. § 418, to secure coverage for the retirement system with respect to which certification has been made. An agreement may be made retroactive to the extent permissible under the Social Security Act.