If there is a screw on the bottom you unscrew it carefully with a well fitted screwdriver. If there is a hole at the top, you drive it out with a punch. If it’s a blind pressed in pin, like the newer ones, you need to drill it out or maybe cut it into segments next to the adjustment wheel. I’ve never done the later. Gearwrench has a patent to make the shaft breakaway by striking the adjustment knob, but I don’t know if it was ever implemented by them or other brands. I rather replace the adjustable or soak it in solvents until it loosens up.
