During shippuden Danzo is able to to cast KA without his MS activated. I know that bandages were covering his eye when he used it on Mifune, but since he transplanted that eye he shouldn't be able to shift from 3T to MS and back. Kakashi can do so because he was near Obito when he awakened his. Itachi's crow was able to do a similar feat, but his was pre-programmed.