Watch-required. Check that bed is locked-required (Imagine if you were about to help a patient stand and as you did the bed went sliding backwards and they tumbled to the floor because their knees buckled, instead of simply dropping back to the bed)
For testing purposes, I don't believe that changing the height of the bed is required, but might as well, for most skills. You would do it in the real world so that you don't ruin your back--so you might as well practice perfect.
Practice does NOT make perfect; only perfect practice makes perfect.