First, you have to get them to realize that they don't know everything. I find that the people who think they know everything actually just fill in the gaps of their knowledge with their own opinions. They are just better at arguing those opinions than the rest of us.
Teach them humility.
You can't reach a person that knows everything. My neighbor and my sister know everything.
Neighbor is always getting herself scammed and having to close her checking account and change her cell number. She has 5 phones and 4 numbers in one year.
If I say someone knows everything, that's just the way I describe someone with a small mind.
Move on to someone who still has the capacity to grow.
I once saw a young guy about 19 reading a chess book on the train and offered to play a game. He sighed but agreed and I pulled out my set. As soon as he told me his name I knew I was in trouble -- he was one of the up-and-coming stars of Australian chess.
Part way through the first game I saw an opportunity but I knew that as soon as I made my move he'd see it too. So I covered it up with a silly comment (blatant cheating in anybody's book). I said, "When in doubt, push a pawn," and did so.
He said, disdainfully, "I never push pawns without a reason," and dismissed the move without thinking about it.
Heh, heh, heh. Neither do I, as it happens.
After the next move he realised that the only way he could stop mate was to give up his queen. After that it was a free run home for me.
His mother, who was sitting next to him, said, "I don't usually see people smiling when they're playing Dan.:
I grinned at her and said, "Dan just learned something."
But he won the next two games very convincingly. No more BS.
If you think you know everything than,
growth is impossible.
Even the ground your standing on
is in flux.
I will leave them alone. If they think they know everything already, then they don't need to be taught. They need to absorb the world and face failures on their own to be able to accept their foolishness.