Always try to avoid it. Avoid starting an adversarial dialogue. But if the other persists and you can’t avoid an adversarial dialogue, you are all-in. So, as already you are all-in, most tactics are acceptable. First, it’s always about the issue, never the person. Thus, no Ad-Hominem remarks! Second, never thrust. Always parry. Best parry: try to move the other off-message and keep the other there. Countering questions with questions is often successful. Finally, try to end adversarial dialogue at the first and every opportunity. It rarely accomplishes anything.