Rule No. 1: RUN. Get as far away from the individual as possible. The good thing about knives is they have limited reach.
Rule No. 2: If you cannot run, put a stationary object between you and the attacker. Find a car, wall, large piece of furniture….something.
Rule No. 3: If you cannot run and there is nothing to put in between, pick something up and start swinging. Try to even up the odds, find a stick, chair or a blunt object of some kind to make him think twice about getting close.
Rule No. 4: If the previous rules are not applicable, then follow the principles of Clear, Close, Control and Capture. Clear all your vitals from the path of the blade. Close the distance by jamming yourself super tight against them, so the attacker cannot swing or stab with the blade again. Control the arm holding the knife as close to the hand as possible. Capture the weapon by any means necessary. That means biting, clawing , striking , spitting, hitting, smashing; whatever it takes to extract it away from the attacker.
As a good experiment, give a person a marker and tell them they can mark you up as much as possible before you take it away. See what happens. It’s often a real eye opener. Have you considered how you would handle a knife attack without a gun?
Read more: Rules for Knife Attack Defense -- Guns & Ammo