Vacancies in the membership of the Commission shall not affect the authority of the remaining members to execute the functions of the Commission, and shall be filled in the same manner and by the same appointing authority as the original appointment, and such person shall serve for the unexpired term of the vacancy. The appointment of any member of the Commission who has been absent and not excused from three (3) consecutive regular or special meetings shall automatically expire effective on the date the fact of such absence is reported by the Commission. Vacancies occurring in the Commission shall be filled within thirty (30) days.