With respect to any franchise, after negotiation or mutual agreement, the Council, by ordinance, may, when public convenience and necessity requires, extend the area to include streets, alleys, or public places and property not embraced in such franchise. The ordinance shall be subject to all the terms and conditions of the original franchise, and co-extensive with the terms thereof, without a vote of the qualified taxpaying electors. (Amended at election held Nov. 6, 1990)