How to stop a Dialog from Sending messages in Portrait Dialogue

Sometimes when using Portrait Dialogue (PD) you may encounter a situation where you need to make PD stop sending out messages.

The quickest and easiest way to make (PD) stop sending messages is to stop the MH Send Message service.
When stopping the service, operations will continue to run and messages will still be generated.  
These messages will be stored in the message manager, but they will not be merged and sent until the service is restarted.

If you want to stop a Dialog from generating messages, you will need to deactivate the operation that is sending the messages.
Alternately, you can deactivate the entire Dialog that is responsible for message sending.  
Operations already executing when the Dialog or Operation is deactivated will continue to run.
Those operations have to be aborted manually using the Execution Monitor.
UPDATED:  April 26, 2017