I agree with trackhappy, don't use pbfree solder unless you have to. Also, if you dont need the job to be tidy. I'd just use a no clean solder, I find Multicore 60/40 511 Crystal solder best. If you don't use a lot of flux at work, it might be cheaper if you grab some flux gel. I use this one at home . You'll find adding some flux on the pin you need to desolder makes a little bit easier. Suck the old solder first with a solder pump until the pin is free from solder, then work on the other pins. Once the component is out then you can thoroughly clean the pads. Adding new solder and sucking it works well, dont forget to add some flux.