A notification of deletion of service/resource is sent by the filler application to other applications when a scheduled appointment requiring a service or resource entered in error has been removed from the system. A delete trigger event should only be used in those circumstances when a service or resource has been erroneously attached to an appointment, and must be removed from the schedule so that it does not affect any statistical processing. A delete trigger event differs from a cancel trigger event in that a delete acts to remove an error, whereas a cancel acts to prevent a valid request from taking place.