I think technically it would be different than rebatching because it hasn't finished saponifying. Also, you don't have to shave it down, and you may not have to add heat to make it gel, either. There's a good chance that whatever caused the seize will create enough heat that the soap will still gel on its own, without an external heat source. I followed cmzaha's advice (just cover it) with my first seize a couple weeks ago, and it was in full gel within about an hour. I was pretty amazed -- and very relieved. It then poured pretty easily into my mold.
If you do add heat to a seized soap, I think it would be more like HP than a rebatch. In any event, a low oven should be fine (warm setting), but I wouldn't put it on a burner unless you have it in a double boiler or have another way to keep it from burning on the bottom. But if you do actively heat it, regardless of the method, I'd keep a pretty close eye on it since the soap gremlins thrive on every chance for chaos! :twisted:
