While in Live Editing View, you can cut between multiple shots, such as close-ups of different people's faces.
To cut to a close-up of a subject in your shot, tap on your subject. You can see what is live in the Program Output view at the top-right of the app. You will also see a wide, blue box over the area that is being shown to your viewers.
"Cut" is a video/film production term for an edit where the view changes in a single frame. An example of this is when you are viewing a wide shot of several people, and then cut directly to a closer shot of a person who is speaking.
For instance, if you have a specific speaker on a panel and want to cut only to that specific person, tap on their face, and the Live Editor will cut to a close up of their face.