The Referral Request State Machine, it would be helpful to implementers to know which state transitions trigger FHIR messaging exchange events. For example, from the End State Description, it's clear if the Finish action results in a message back to the Referral requester (or what other "in progress" triggers exist). A column added to the State Transition Trigger Events indicating a message trigger may make things clearer. As well, it would be nice in the scoping section that cancellations and withdrawls are in scope for messaging.