DICOM PS3.18 2019a - Web Services
6.9.2.3.2 Response Headers

If the UPS instance was updated but with modifications made by the Origin-Server, the response message shall include the following HTTP header:

If optional attributes were rejected, the response message shall include the following HTTP Warning header field:

If the request was rejected with an HTTP 409 status code, the response message shall include one of following messages encoded in an HTTP Warning header field describing the nature of the conflict:

DICOM PS3.18 2019a - Web Services