After January 1, 1970, any municipality may by charter, or by vote of the legislative body approved at a referendum of the electors to be held within thirty days thereafter, change the date of its municipal election by designating the alternate date specified in section 9-164 as the date of the municipal election, provided

1. (1) no such charter provision adopted, nor such vote of such legislative body so approved, within six months prior to any municipal election may be effective with respect thereto, and
2. (2) in changing from the November municipal election date specified in section 9-164 to the May municipal election date therein specified, the terms of incumbent municipal elected officials shall be diminished to conform to such change but for a period of not more than nine months and
3. (3) in changing from the May municipal election date specified in section 9-164 to the November date therein specified, the terms of incumbent municipal elected officials shall be extended to conform to such change but for a period of not more than nine months.

(1969, P.A. 570, S. 5.)