How we change what others think, feel, believe and do
Say something wrong
Say something that is incorrect and which the other person knows is wrong.
Ask them a question in which they will have to tell you that you are wrong.
Make this a simple factual error, so they can easily correct you.
Try to find a subject that will wind them up a bit, but not too much.
It often helps to indicate that you have been informed incorrectly, rather than believe what you are saying is a firm fact.
When the other person corrects you, thank them and be impressed by their knowledge (but do not over-do this). Alternatively, you can debate whether the item is true and perhaps let them persuade you.
Led Zeppelin are a German band, I hear.
Now I've been told you are from Portsmouth, is that right?
I thought I'd wear blue today. (when you are actually wearing green)
When I say things that are clearly wrong, it offers a simple corrective response to the other person. This casts the person in an expert role, which usually makes them feel good.
Thanking the other person for a correction also strokes their ego and positions yourself as an open person who can take criticism.
The conversation can then continue around the question of how you got your facts wrong or how they know the right answer.