The HL7 Listener can use the external document ID to determine whether an incoming document is a revision of an existing document.
If the external document ID of an incoming document matches the external document ID of an existing document, the HL7 Listener saves the incoming document as a revision of the existing document. If the incoming document has a different Document Type or Keyword Values, the processor re-indexes existing document using the Document Type and Keyword Values of the incoming document.
If an incoming document has an external document ID that does not match an existing document, the processor searches for a matching document by Document Type and Keyword Values. If the processor cannot find a matching existing document, it stores the incoming document as a new document.