How do I replace the ignition lock cylinder?

I will attach the info from the manual below. However, I suspect you want to replace the switch because it is damaged or even you have the key stuck in it.

This was a common issue on these older GM products so here is a guide that will help with this:

https://www.2carpros.com/articles/ignition-switch-wont-turn-stuck

After running through the guide, the info from the manual is above.

Please let me know if you have other questions or need more info.

Thanks