At any point in time, you can stop, make centre trim adjustments to move the edit dynamically up and down the timeline, extending off the outgoing shot and cutting into the incoming shot or vice versa.

If you made a previous camera choice and which to change the camera to another while maintaining the same duration of the edit, simply use the home row keyboard, which will switch the camera but not add an edit point like the number pad. 

This is immensely useful for those times that you inadvertently switched the camera by accident or simply found a better angle to tell your story.