Whenever the public necessity, convenience, general welfare or good zoning practices require, Council may by ordinance, after receipt of recommendation thereon from the Planning Commission, and subject to the procedures provided by law, amend, supplement or change the regulations, district boundaries or classification of property, now or hereafter established by this Zoning Ordinance or amendments thereof. It shall be the duty of the Commission to submit to Council its recommendations regarding all applications or proposals for amendments or supplements.