After a hearing is scheduled and notice is given to the party or parties as herein provided, a postponement or cancellation may be had by any party only for good cause. A request for postponement or cancellation shall be first and promptly made by telephone or in person to the presiding board member. If the request is granted, the party shall confirm the request and the grounds therefore by letter to the board member, with a copy thereof being delivered to the opposing party/parties or counsel.