“Huh, I never thought of it that way”
I’m afraid I can’t locate the source, but I once heard something that I’ve found to be very powerful:
When you are debating someone, first give their idea five minutes. Don’t look to bash it right away; first try to believe in it.
Then, reframe it so well that they nod along, saying “huh, I never thought of it that way.”
Then, and only then, offer your counter-argument.
I’ve found this approach invaluable.