Matched on: [[Encounter.External Encounter ID]] as derived from PV1-19.1
When matched: The [[Encounter Event]] will be handled as indicated below.
When not matched: Since this is a cancellation message, no action will be taken.
Matched on: Transfer [[Encounter Event]]s are not uniquely identifiable. Instead, matching is done based on timestamp.
When matched: If there is one or more transfer [[Encounter Event]] associated with this [[Encounter]], the most recent will be deleted.
When not matched: No action.