The legislative body of a county, city or city and county, may by resolution adopt a name for any street, boulevard, park or place which is to be improved under this division, for which a name has not been provided under the provisions of Sections 970.5 and 971, or otherwise, and may by resolution change the name of any street, boulevard, park or place heretofore established; provided further, that a copy of the resolution or order providing for the new name or change of name made by any city shall be promptly forwarded by the city clerk to the clerk of the board of supervisors and county surveyor of the county in which the municipality is situated.