(a) Increased municipal territory.--If a municipal corporation gaining territory is divided among wards, the governing body shall, within 30 days after the change in boundaries is effective, provide for the distribution of the gained territory among the wards of the municipal corporation or for the creation of one or more wards out of the gained territory. (b) Decreased municipal territory.--If the municipal corporation decreasing territory is divided among wards, the governing body of the municipal corporation shall, within 30 days after the change in boundaries is effective, provide for the alteration of wards among the remaining territory.
Pennsylvania Legal Code