Question about soldering/desoldering
The solder needs to be melted and physically removed while in its molten state. Applying the soldering iron tip it will only melt it, you need something else to remove it.

Use a "solder sucker" for this job. It is a small spring loaded vacuum pump designed to, well, suck solder away from a joint. You can get them from any electronics hobby shop.



First, apply heat to the joint until all the solder is melted. Next bring the tip of the solder sucker right up to the joint and release the plunger. The final result should be that most of the solder is gone (some will be left behind but that is usually ok). take your iron and lightly push on the joint until you feel the lead loosen, then move onto the next joint. If a small amount of solder remains and you can't loosen the joint, apply more solder and use the solder sucker again (you need an amount of solder on the joint for the solder sucker to work).