I think you posted in the wrong forum. You would get more replies in reef discussion or lps. If the polyp (flesh part) poped off of it's skeleton it's done. You can't reatatch the flesh. You need to post all of your water peramiters - salinity, alk, calc, mag, ph, temp, ammonia, nitrate, nitrite. How did you aclimate it? There is a chance the skeleton may grow a new polyp so don't remove it.