Springs can get "re-arched" with the proper equipment. Not many shops are capable of doing this, though, and it's my understanding that with the cost associated, it usually ends up being close enough that you'd just as well have replaced the springs.
Not to mention that re-arching a spring generally tends to weaken it, or it will still be soft as it is still the old spring, just with a little more bend. If you can get them done properly it may work out well, but all the people around me I've talked to who re-arched their springs (we have a shop who can do them around here) recommended to not bother with it.
It was a great option back before the aftermarket really kicked up with lift kits, but now it's kind of an outdated procedure.
