Is it completely white or does it still have some tissue? I would put it in a spot with low light to prevent any further shock to the coral. Could you post any pics?
If it is bleached(white but still has tissue) it can recover a small percentage of the time. If it is white from tissue necrosis(skeleton with no tissue or polyps left on it), then it is dead.
if there is any tissue left there is a great chance it will regrow. a lot of sps's can discolor from shipping or even moving from one tank to another just down the street.
was there color in it when you got it?
did you see string of tissue coming off it?
do you have any other sps's or even lps's in the tank?