You could cut it right down the middle or cit it in four. It should heal up just fine. Its a little scary at first but i have done this a few times and always had success. I recently had some issues with my toadstool leather coral. It had some type of white parasite on it and it almost completely died. I ended up taking it out of the tank and cutting into it to see if I could salvage any of it. I ended up with an 1"x1" square from the core and it is developing a new head with polyps now.