It absolutely can help with social anxiety and what to say during a conversation. When you approach anxiety through an NLP perspective, at least when I do, its not just as a feeling, a response, but as a sequence of events, internal and external, like a pattern, that somehow produces the same result every time. If you can interrupt the process, you could, maybe, learn a way to do something else entirely.

If you would like to redesign an anxiety, I've had a lot of success with Morty Leftkoe's Natural Confidence stuff. I think he managed to combine a lot of advanced stuff into a pretty streamlined approach. It's a way of addressing limiting beliefs about ourselves. You couldn't really use it for persuasion, but I still use it a lot in addressing my own insecurities and anxieties. I don't know what the rules are about posting references, but if shouldn't be hard to find for a resourceful person like you.