They are one of the easier LPS to frag.
Irritate the coral while it's under water by moving it up and down and back and forth until it pulls in all of it's polyps.
Grab a dremel. One of my favorite bits is the fiberglass reinforced cut-off bit
Fiberglass H/D Cut-Off Wheel (5) (dre426) Dremel Mfg. Co. Power Tool Moto-Tool Cut Off Wheel for small to medium-sized specimens. For larger specimens, you can buy larger cut off wheels or simply use the smaller bit to score the skeleton very well, then use a hammer and a flathead screwdriver inside the groove you've scored and give it a whack.
Now that all of the polyps are in, it's very easy to see the coralites of each poly. Obviously avoid those while cutting the colony to size.
Place in a separate tub of tank water for about 15 minutes to make sure none of the polyps slime up and GENTLY agitate the water to remove the dust and particles created by the dremel.
Return to tank. Replace carbon in the tank at the same time.