From a little bit of thinking, this is what I concluded: A system initially at rest can change its angular position without any outside torques (the final state will also be at rest). A system initially at rest cannot change its displacement without an outside force. In other words, cons. of linear momentum also implies that a system cannot move its CM without outside forces, however, cons. of angular momentum does not prohibit a body from changing its angular orientation without outside torques, due to the fact that rotational inertia can be changed internally. Is this correct, or can anyone offer counterexamples?