It should reattach using the netting, but sometimes the decreased flow can cause tissue to die or the sarco will attach to the netting. You could also try to just rubberband it onto a rock, but sometimes you have the same issue (although not nearly as often). I use the rubberband method alot. Its quick, easy and cheap. I sometimes will also take fishing line and sew/thread it through the coral once and tie it to a rock. Once it attaches I cut the line and pull it out. I usually only do that with sofites that seem to be a pain to attach in other ways. It works nicely though because there is such a limited area in contact with the fishing line and there is rarely, if ever, any tissue death.
