You can change this per subscriber under Subscribers > Conversation > Message Addressing and Sending. You can also change this for new subscribers by modifying a subscriber template. If you want to change a group of (or all) existing subscribers, use Bulk Edit in the Tools Depot.
Users can also change this on the fly by pressing ##.
These are the paths to get to each CCX logs through CLI. They may be helpful if you are having issues accessing RTMT or downloading logs through it.
If you want to download them you have to prefix "file get " and you can add one of the options (re...