Four members shall constitute a quorum. The affirmative vote of four members shall be required for passage of any matter before the Commission. The minutes of the meetings shall reflect the "ayes" and "nays" cast on a particular measure and shall reflect the vote of each member present. A member may abstain from voting only upon a declaration that he or she has a conflict of interest, in which case the member shall take no part in the deliberations on the matter in question.