N.J. Stat. § 16:11-13: Vacancies of trustees or officers; filling

Whenever a vacancy shall occur in any board of trustees, the remaining trustees shall constitute the board until the vacancy is filled. The vacancy may be filled for the unexpired term either at a special business meeting of the congregation duly called for that purpose or at the next annual business meeting of the congregation. Whenever a vacancy shall occur in the office of president, the trustee of the board, senior in age, shall be president pro tempore, and the board shall elect one of its number to fill the vacancy for the unexpired term. A vacancy in the office of secretary or treasurer, or in the auditing committee, shall be filled by the board of trustees electing a person to fill the vacancy for the unexpired term.