To replace a bushing while the component is still on the car can be done for some parts. You need access to the bushing and so other parts have to move away. This is an example of when you can get access to the bushing.
The car is a 1996 Lincoln Mark IIIV, in this case the rear upper control arm outer bushings were worn to the point that it would case the tires to wear out on the edges. After replacing the bushings the tires would wear properly. It would also rattle and make a thunk sound when going over a bump.
The camera was an old Kodak Z650 that I have has for 10 years and had used to make several videos before 2012. I thought I had lost this video until looking for another file I found it, so I edited it to show the process and tools that are needed.
Very large sockets like the one I used come in handy for pressing out parts like bushings.