Thanks, I was thinking it was like transmission fluid and if I did a drain and fill there would be a lot of old(possibly dexcool) coolant in the colling system.
I didn't want to mention it because some may not approve, but I also plan on using a pella extractor where you slide a tube down the dip stick or in this case radiator. I live in a condo complex where you can't work on your car, so I'm thinking using an extractor may be better than not doing anything or mixing coolant.
A few years ago I bought a car that had green over red(made mud) and it was a mess to get totally green.