#1 Rack focus
I am sure you have watch this in many movies like it focus on one subject and then focus on another one without changing the scene. It is called rack focus.
#2 Focus pulling
This technique is the most common one where the subject is moving and the camera is moving with it and the subject is always in focus. Same as auto focus but doing it manually is called focus pulling. continuously changing the focus ring manually to keep the subject in focus.