When there is a permanent vacancy, the Board of Selectmen must appoint a new member to serve for the remainder of the unexpired term. A vacancy occurs upon the resignation or death of any member, when a member ceases to be a legal resident of the Town, when a member fails to attend four consecutive regular meetings, or fails to attend at least 75% of all meetings during the preceding twelve-month period. When a vacancy occurs, the Chair of the Planning Board must so advise the Board of Selectmen in writing. The Planning Board may recommend to the Board of Selectmen that the attendance provision be waived for cause, in which case no vacancy will then exist until the Board of Selectmen disapprove the recommendation. The Board of Selectmen may remove members of the Planning Board by unanimous vote, for cause, after notice and hearing.