Pour some hot water (kettle is good , be careful, )over the ferrule and slide it up shaft a bit , clean and put some expoy on shaft and slide ferrule back down,
Clean excess expoy with white spirit before it dries.
Does not need to be epoxy if you are glueing it (epoxy is really for club head to shaft for a really strong grip) you can just use a little bit of super glue or plastics glue.
You may need to re-apply hot water to get it to slip back down in place.
As said ferrules on graphite shafts are for cosmetic purposes only.