You’re free to leave any meeting at any time. If you’re stepping away and will return it’s useful to activate your stepping away emoticon (in the Participants / More.. window) so if I want to ask a question I know you’re not available at that moment but will look back later when you return. At the end of any meeting I, as the host and presenter, end the meeting for everyone. You don’t need to do anything. Once I end the meeting for everyone you’ll automatically find the meeting ends on your computer or device.