I believe the feature you are looking for is called Barge/cBarge
Barge adds a user to a call that is in progress. Pressing a softkey automatically adds the user (initiator) to the shared-line call (target), and the users currently on the call receive a tone (if configured). Barge supports built-in conference and shared conference bridges.
The Single Button Barge/cBarge feature allows the user to simply press the shared-line button to be added to the call. The Single Button Barge/cBarge feature supports built-in conferences and shared conference bridges.
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...