When such a petition is filed with the Clerk of the Council, the Clerk shall determine the sufficiency in valid signatures. If the petition be found sufficient, or be rendered sufficient by amendment, the Clerk shall certify that fact to the Council, which shall proceed to reconsider the ordinance. If upon such reconsideration the ordinance be not entirely repealed, the Council shall, at its next regular meeting, provide for submitting it to a vote of the electors.