How to replace radiator drain petcock??

Hi!

The (stock) radiator drain petcock on my '95 Caprice has been leaking a bit lately, so I decided to get a new one. It would be nice to just pop the old one out and new one in, letting as little coolant out and as little air in as possible.

So the question is, how is the petcock removed and installed? Does it come right out if I twist it to some specific position? Or, do I have to twist it to some specific position and then somehow drive the pin out, or something like that?

Thanks!