The Commission may review any franchise now or hereafter granted by incorporated municipalities of this State which, on June 28, 1974, have the power either express or implied under their charters to grant franchises for a system for the construction or operation of cable television systems within their boundaries, and whenever the public interest requires, change or modify such franchise or the conduct of the franchisee thereunder so that such franchise or such conduct complies with the provisions of this subchapter governing franchises granted by the Commission. If such a municipality refuses to grant a franchise and the Commission finds that such refusal is not in the public interest, the Commission may award a franchise under this subchapter.