I was trying to answer your question convincingly. Sorry if my post came across the wrong way.
Since intimidating to demoralize gives the Shaken condition, I think of it more as trying to throw your opponent off balance with the right words, gestures, and expressions. That might mean standing in a way that emphasizes your strength, smiling at the thought of combat to project confidence, or describing just how you're going to cut your opponent to frighten them. By the rules alone, I don't think you can demoralize someone into backing down completely. Of course, a good GM might decide that being shaken is enough for someone to surrender, especially if the odds are clearly against them.
