Where would wrenches go? Does it need to be cut?
It looks like galvanized pipe but I think it's tind copper due to the valve not having a hex shoulder. I'd say take a sharp blade and carefully scratch a layer off the pipe to confirm that it is copper. If so. Cut back after shutting off the water. Clean it with sandpaper until it shines better then new. Then clean it again. Flux and solder. If you are not comfortable soldering, you can use a push on fitting like a Sharkbite.