Don't take your eyes from the knife assaulter; Try to guard your vital points - Neck, eyes, chest, groin; Give as fast what the assaulter asks, cell phones, wallets, money and try to distance as faster; Talk the necessary and keep a distance to go away; In case of an attack follow the sequence: Run away; Shelter - Hide Ballistic - search something to throw and keep distance; Shield - Put something between you and your agressor; Combat - Start the combat but guard your vital points, in case of defense, hide your tendons. Only go into a fight in last case; After disarm the knife, don't try to keep the fight, you have the advantage now, so use it at your favour, run away, he will probably won't follow because you have the weapon; In case of counter attack, search the vital points to disable him. Remember your life is more important than any material well. Use the legislation at your favour!