5.2.3. Message Rejection

After acquiring a message on a reliable link your application can reject it. When a message is rejected the broker will delete it from the queue. If the queue is configured with an alternate exchange, then the rejected message is routed there; otherwise it is discarded.
To reject a message using the Python API, call the acknowledge() method of the session, passing in the message that you wish to reject, and specify REJECTED as the Disposition parameter:
Python
msg = rx.fetch(timeout = 1)
    
if msg.content == "something we don't like":
  ssn.acknowledge(msg, Disposition(REJECTED))
else:
  ssn.acknowledge(msg)
Note that this is only possible when using a reliable link. When using an unreliable link, mesages are implicitly acknowledged when they are fetched.