To switch between loaded meetings in LiveManager, just select the meeting from the menu available.
About Switching Meetings
When you load two (or more) meetings in LiveManager, Meeting A will pause if you switch to Meeting B, and then Meeting B will pause if you switch back to meeting A. However, a meeting doesn't "pause" like when you might press the Pause button; what technically happens is the encoder records one video, then in post-processing it splits up the video segments and matches them to the archives accordingly. Two archives will be created, and the archive duration will reflect the total length of time the agenda was active in LiveManager; so if you run Meeting A for an hour, then Meeting B for an hour, and then Meeting A for another hour, the duration of each archive would be: Meeting A - 2 hrs, Meeting B - 1 hr.
You can switch back and forth as many times as you want, LiveManager will always match the video to the proper agendas/archives.