Updating a resource
When updating an element, the REST operation is a PUT.
First, you must execute a GET operation on the element to retrieve the ETag from the HTTP header.
After modifying the JSON/XML element content, you can execute a PUT operation with the ETag value in the If-Match request header parameter. The If-Match header parameter is required to make sure that the version element is the most current version.
It is important to modify the results of the GET execution to make sure that all attributes are present for the update (for example, the key).
No merge is done for collections during an update. The API replaces the existing resource with the new one.
If the execution succeeds, it returns a 200 HTTP response status code and, in the HTTP header, the updated element API's URI.
Tip: The Content-Type HTTP request header determines the input format (XML or JSON).