Council may appoint not more than three qualified electors of the city to serve as alternate members of the civil service board. The term of office of the alternate members shall be four years. If, by reason of absence or disqualification of a member, a quorum is not reached, the chairperson shall designate as many alternate members of the board to sit on the board as may be needed to provide a quorum. When seated pursuant to this section, an alternate shall be entitled to participate in all proceedings and discussions of the board to the extent as provided by law for board members, including the right to cast a vote as a voting member during the proceedings, and shall have all the powers and duties set forth in this chapter and as otherwise provided by law. Any alternate member of the board shall continue to serve on the board in all proceedings involving the matter or case for which the alternate was initially designated until the board has made a final determination of the matter or case. Designation of an alternate pursuant to this section shall be made on a case-by-case basis in rotation according to declining seniority among all alternates. Alternates shall hold no other office in the city. Any alternate may participate in any proceeding or discussion of the board but shall not be entitled to vote as a member of the board unless designated as a voting alternate member pursuant to this section.