Petitions duly signed, may be presented to the City Recorder requesting an amendment, supplement or change of the regulations of this Ordinance by:
(a) The Planning Commission.
(b) By sixty percent (60%) of the property owners according to the frontage in any district, or portion thereof, as large as the City block between two parallel streets, together with fifty percent (50%) of the property owners according to frontage on all blocks immediately adjoining and facing any part of the blocks immediately adjoining and facing any part of the block or district proposed to be changed or amended. (Ord. 9-3-68.)