can you take out Fiery (or other) and put another prefix?

Say you have a Fiery Hammer, and you want to take out the Fiery Prefix and put in say a Shoking haft. Is that possible? What about the chance rate?

You can apply the shocking haft to the hammer and get it to do electrical damage, but you can't remove a modification that's already in place without destroying the hammer. If you apply the shocking haft to the hammer the fiery haft is gone; if you salvage the hammer there is a chance you get the firey haft or a bunch of wood.