as others have said it all depends on which one you have the new hasbro FX's are slightly different from the older MR versions, generally the blade has one or more set screws holding it in that require an allan wrench to remove, you'll likely have to pry some sort of cover plate away to get to the screws.
oh forgot, it's a component blade as well so you'll also need to remove the electronics and disconect the blade, at that point you could probably go whole hog and convert it to a luxeon setups with one of the kits sold by the custom saber shop or ultrasabers.