I have a new boot to install on my B6100 transmission shift lever and I am not sure if the knob comes off to do it or if I need to take the top cover off of the transmission and remove the lever that way. I don't want to create a problem fixing one.
The knob should come off the lever. It isn't threaded, so it will pull off, however this could take some doing as sometimes they are "stuck". Just keep working at it and it will come.
I have replaced the boot on B6200 at least 3 times in 24 years. Heat the rod just below the knob with a propane torch just enough to break the glue bond.
I ended up threading the rod and making a new knob with matching threads.