From the pic it looks like its on a tiny peice of rock. You can take the rock you want it on out of the tank, then take the polyp out of the tank dry off the bottom of the rock the polyp is on and then dry off the area of the rock you want it on, then use a gel superglue and glue the polyp on the tiny rock onto a bigger rock for placement.
Let air out for a min or so then drop in some tank water tha you have put in a bowl or something similar and let the glue cure for about 15 mins in the bowl underwater before returning it to your tank