This procedure is similar to detaching and reattaching a skeleton, except that it only applies to selected joints.
Detaching selected joints from the skin objects they influence unlocks the transform attributes of the objects so that you can reposition them. Detaching selected joints preserves the rigid skin point sets and the rigid skin point weights. Detaching and reattaching selected joints is especially useful if you want to move, rotate, or scale certain skin objects directly while not changing which joints influence which rigid skin points.
To detach selected joints
To reattach selected joints