A request discontinuation of service/resource is sent by the placer application to the filler application when the remaining occurrences of a recurring appointment no longer require a particular service or resource. In other words, this trigger event is sent to request that the performance of a service or resource in a recurring appointment that has already begun be stopped. If the first appointment in a set of recurring appointments has not yet occurred, then a cancel trigger event should be sent instead. This trigger event should only be used on appointments that have not been completed, or on parent appointments whose children have not been completed. If it is successful, an application acknowledgment is returned, optionally containing an SCH segment and related detail segments describing the modified appointment.