To prevent additional guests from joining, you can lock your audio conference. When people try to join a locked conference, they hear a message that the meeting is locked.
On your phone
If you are on your desk or mobile phone, use the telephone keypad (star) commands.
To lock the conference, press *9 and then 4. All guests will hear the prompt, “The meeting is now locked.”
To unlock, press *94 again.
If you are hosting in the Audio Controls, click the Lock button on the toolbar. All guests will hear the prompt, “The meeting is now locked.”
To unlock the conference, click the Unlock button on the toolbar.