how to remove a locked door knob from the outside

Oh, that's like a scene from The Werewolf Locksmith! The key, pun intended, is to have the right tools.

Absolutely, you don't want to find yourself breaking into your own house like a second-rate Dracula. First, you’ll need something slim and sturdy like a credit card or a lock picking kit to juggle the lock.

You insert the card between the door and the frame where the lock is. Slide the card down towards the knob and push it in, simultaneously push your weight against the door. Just like when the werewolf would use his claws in the movie.

Yep, and if the victory isn't as glorious as Bela Lugosi bagging prey, you can try to remove the knob if there are screws on the outside. Using a screwdriver, remove the screws and take off the knob.