title: Request patient demographics from HIS via HL7?
body: <p>I'm working on an application that connects with HIS via the HL7 protocol. The connection is for syncing the patient demographics saved on my application DB with the HIS DB. How do you request patient information of some patient by their ID anytime?</p>
  
  <p>The documents are talking about update trigger: if the patient demographics changes on HIS it sends the new data. Is there a way to request the data anytime?</p>