Reed switches are easy to desolder or solder. The main concern is that if you bend the leads or mess with them too much, they can break/stop working properly. It's also absolutely essential that you bought the right ones! If you have normally closed and you got normally open ones, they absolutely won't work.
There's soldering tips online, but here's an overview. When you're desoldering, hold the iron on the solder bead until you see it go liquid, then carefully pull the part out with pliers, one end at a time. If there's any solder left, clean it up with desoldering braid the same way. Braid lasts a bit longer if you open up its fibres a bit. Then, put the new reed switch in the same spot, wrap the wire around the lead if you can, then hold the soldering iron on the metal for a few seconds, then tough the solder to the tip of the iron. If it doesn't flow cleanly around the wire, remove any solder that's left with braid, and try again, this time holdinh the iron on the metal for a little longer.