Any person who retired under the San Francisco City and County Employees’ Retirement System from an employment status in which he was a member of the State Teachers’ Retirement System, and whose retirement was effective after June 30, 1955, and not later than 90 days after February 1, 1957, may elect, in writing on a form provided by the Retirement System and to be filed at the office of said system within 90 days after February 1, 1957, to relinquish his right to a retirement allowance from said City and County Employees’ Retirement System. If such person so elects to relinquish said right, his retirement allowance shall be cancelled forthwith and no payments of such allowance shall be made to him, or on his account, for time on and after the effective date of such election, and such election shall be irrevocable. The San Francisco City and County Employees’ Retirement System shall pay or be liable to pay to or on account of such person, only an amount equal to the actuarial equivalent, as of the effective date of such relinquishment, and on the basis of the mortality tables and interest rate then used under the system, of the portion of the cancelled allowance which was provided by said person’s accumulated contributions at the effective date of his retirement. An amount equal to such actuarial equivalent shall be forwarded forthwith to the Retirement Annuity Fund of said State Teachers’ System, to be applied on the amount due to said fund from said person under the provisions of Division (7), Chapter 14 of the Education Code of the State of California, but not to exceed the amount so due as may be quoted in a written statement requested of and received from said State Teachers’ Retirement System as applied to any person herein involved. Any excess of the actuarial equivalent over said amount so quoted as due shall be paid forthwith to said person.