[Olm]

I understand it that after you announce it you may not attack for 3 turns.
So if it is declared before turn 40, 40,41 and 42 are the turns you may not attack. If you cancel ingame with a message arriving with turn 39 you still may not attack on turn 40,41 and 42. Thats how I would understand it. In both cases turn 39 is over, I couldn't change anything in that turn. Even so you could wait until only your turn is missing. Then cancel the NAP in the Forum and immediately send in the turn, that would cut reaction time to two turns with a quite dirty trick. I would still call that breaking of a treaty.