Ignition installation

Unfortunately the only option when this happens is to drill it out so the tumblers are no longer catching and then turn it and remove it.

However, before you replace the switch, have you tried a new key? Usually when this issue happens it is because the key is worn so much that it no longer moves the tumblers to the correct position to allow the cylinder to turn.

I would suggest trying a new key before you drill out the cylinder.