# 409 Conflict

       The request could not be completed due to a conflict with the current
       state of the resource. This code is only allowed in situations where
       it is expected that the user might be able to resolve the conflict
       and resubmit the request. The response body SHOULD include enough
       information for the user to recognize the source of the conflict.
       Ideally, the response entity would include enough information for the
       user or user agent to fix the problem; however, that might not be
       possible and is not required.

       Conflicts are most likely to occur in response to a PUT request. For
       example, if versioning were being used and the entity being PUT
       included changes to a resource which conflict with those made by an
       earlier (third-party) request, the server might use the 409 response
       to indicate that it can't complete the request. In this case, the
       response entity would likely contain a list of the differences
       between the two versions in a format defined by the response
       Content-Type.