If you want to break it off, I would wait a bit longer, until it has at least a couple of inches of skeleton separating it. Then you should be very careful separating the two halves so as not to tear the tissue. I have never done this with anything but a branching type coral, I have read, however, that a dremel comes in very handy for this type of job. If it were me (unless I were pressed for space), I would allow nature to do it's thing, but that is just me.