Not really confident, that's why I'm trying to understand what's happening.

Both Nacks have MSA segment, but one of them contains AE and the other contains AR.

Yes I can assure you that both of them are for the same operation.

Code Action was E=F,R=F and then changed to E=F .. Regarding the sync/async incoming request..  Nothing changed on TIE, we're using the MLLP framing, could this be controlled by the source system? and yes the business operation is the same component/host.

Hi Luis,

Thanks for your response.

1-Does that mean that the current built in process does not support the PUT/DELETE by default and I have to amend the code?

2-In regards to the identifier (id) for patient resources, I attempted to utilize the Medical Record Number (MRN) as the identifier. However, I observed that the FHIR server consistently assigns a different numerical value, potentially through an auto-incrementing mechanism. Does this imply that modifying this identifier is not permissible? Additionally, is it necessary to initiate a GET request to retrieve the resource identifier before executing a PUT request for updating patient information?