Unless the authority elects to convert into a regional metropolitan transit authority pursuant to the Regional Metropolitan Transit Authority Act, the governing body of the authority shall be a board to be known as The Transit Authority of ............., filling out the blank with the name of the city, which shall consist of five members, to be appointed as provided in section 14-1813. If at any time such authority elects to convert into a regional metropolitan transit authority, then as of the effective date of such conversion, the governing body of a transit authority established under the Transit Authority Law shall become a board known as the Regional Metropolitan Transit Board of . . . . (filling out the blank with the name coinciding with the name of the regional metropolitan transit authority determined pursuant to section 18-804). Thereafter, notwithstanding any provision in the Transit Authority Law to the contrary, such board shall consist of members as determined under and be governed by and subject to the Regional Metropolitan Transit Authority Act.