Pivot shoe removal for a vinyl covered aluminum window

That depends on the type of pivot shoe you're dealing with. Assuming this is a tilt window, there is usually a cutout at the top of the track that allows you to pop it out. You'd just first have to remove the balance to clear the way.

That's just one possible method, though. There are many different pivot shoes for many different windows. Seeing a photo of what you have now would give me a better idea of what you're dealing with and what you may be able to do about it.