Ignition Change on 1995 Mercury Cougar

Tore down column to access ignition.
Pushed tab to release ignition but nothing happens. Anything I'm missing??

2 answers
My book says the lock cylinder needs to be in the "Run" position before it can be removed. It says there are 2 retaining screws on the switch that need to be removed before it will disengage from the actuator. The new lock cylinder should also be in the run position before it is installed. Once everything is back together verify the switch is adjusted properly so it functions in ACC and start. hope this helps
trying to replace ignition switch ,but cylinder will not go all the way in slot.