70 ILCS 200/55-30
Members of the Board, except additional members appointed by the Board, shall hold office until their respective successors have been appointed and qualified. Any member, except additional members appointed by the Board, may resign from office to take effect when his or her successor has been appointed and has qualified. An additional member appointed by the Board may resign from office to take effect upon the date the member specifies. The mayor or president, as the case may be, with the advice and consent of the corporate authorities of the municipality, may remove any member of the Board appointed by him or her in case of incompetency, neglect of duty or malfeasance in office, after service on the member, by registered United States mail, return receipt requested, of a copy of the written charges against him or her and an opportunity to be publicly heard in person or by counsel in his or her own defense upon not less than 10 days notice. In case of failure to qualify within the time required or of abandonment of office or in case of death, conviction of a felony or removal from office, a member's office shall become vacant. Each vacancy shall be filled for the unexpired term by appointment in like manner, as in case of expiration of the term of a member of the Board.
70 ILCS 200/55-30