1998 Sonoma sliding window

I want to put a sliding window in my friends truck but not sure how hard the stock one is to get out.Can anyone help?

I suppose it depends if you want to save it or not :)

Haven't done it before, but I'd take a look at the replacement and seeing if its the rubber rectangle thing. They're not too bad. A spray bottle with soapy water may help things slide in and out.