@ramyasam this plugin was developed with the concept of fiverr platform communication system. And communication thread is associated with the user profiles. As long as your users exist, thread will remain in database. If you will delete user, message history will be removed as well.
If you are talking about deleting a message within a few minutes or you are asking about the correction mode. That feature is not yet released for this plugin. Kindly wait and consider it as a feature request.