Within five (5) working days of the date that a complaint was filed, the Commission shall conduct a preliminary review of each complaint and determine whether an investigation of the alleged misconduct is warranted, whether the matter shall be mediated or whether no further action is necessary. This decision shall be made in accordance with the rules promulgated by the Commission. Preliminary review may be waived with the unanimous vote of the Commission to proceed with an investigation. All complaints shall be kept on file regardless of whether an investigation is initiated.