N.J. Stat. Ann. § 40:41A-6

Any vacancy occurring in any of the offices held by the seven elected members to the charter commission shall be filled by the unsuccessful candidate who shall have received the greatest number of votes in the charter study commission election if he shall be available to fill such vacancy. In the event that the vacancy cannot be filled in this manner, the remaining members of the charter study commission shall appoint some other properly qualified citizen. Any vacancy in the office of any of the appointed members to the charter study commission shall be filled in the same manner as the original appointment.