If it's just bent, and in my experience even new rotors can have a small bend, then yes it can be straightened. If it is actually warped, I think replacement is the only option, because you'll just end up chasing the "bend" round and round the rotor
Have you tried straightening it? Find the section where it's rubbing and bend the rotor gently in the required direction with a (clean) adjustable wrench
If it is bent from a hit then possibly it can be straightened but if it is warped through heat - whether dragging it or just using it too much then there is little that can be done as if you straighten it, then it will just warp under heat again.