I'm a blender noob.
I obtained a blender model which has two rigged low-poly hands attached to an armature with shoulders and arms.
I'd like to edit it so that it only has the right forearm and hand.
I think that I should be able to do this by selected the relevant bones and then using ctrl-alt-p to make the arm a separate armature.
But no matter what I try that command doesn't seem to do anything.
I'm using Blender 2.79, on a Mac.