This is something that the nimblest standup comedians learn, over time, to handle gracefully. They'll go between prepared material, then they'll respond to what's happening in the room and weave it back into the prepared material and so on.
John HodgmanI naturally own a lot of very old magazines. And I enjoy going to old magazines because the advertisements in those magazines tended to have thousands of words of copy in them.
John HodgmanThe reality is that if you want to be in a reality-based community, you've got to respect reality and that means calling it bad when you see the past ahead and it doesn't look good and acknowledging when it's going to work.
John Hodgman