Mutual Exchange Achievement
Trade Officer with another player for the first time.You do this by hitting and going to the trade officer icon while connected online with other players. You could trade and not save, or you could trade for real. If you trade you must use the officer in a battle in your strike force (go to shrine and guests) before you can retrieve them. Take note that if you complete 10 battles for each other and trade back, your officer/s will now be a type+ and will have gained experience. Awesome!