How do I get the turn signal cancelar plastic piece out of steering column

The page at the link below is for 1970 cars with the tilt column so unless some the changed, it should pull out after the three screws are removed.

https://www.hamtramck-historical.com/images/serviceHighlights/70 sh 196.jpg

There are other pages there that are tilt column specific at well, they start with page 45, so you may find more of use to you there.

The 1970 Hamtramck Registry - 1970 Passenger Car Highlights - Steering