1997 Ford Thunderbird turn signal - emerg flasher problem

Sometimes my turn signals and/or emerg flashers don't work. I am trying to remove the turn signal module from steering column so I can check it out for dirt, bad connection, etc. However, I am unable to remove the upper plastic cover behind the steering wheel because the ignition switch turning knob covers and blocks the hole that the ignitiion switch goes through on the plastic cover. I need to remove the cover to access the mounting screws for the signal module.

How do I remove the external ignition switch knob?

Thanks