When you need to have a tense conversation, don’t try to wing it. You can’t know how the discussion will go, so think through a few possible scenarios ahead of time. What if your counterpart gets upset and cries? What if they get angry? What if you get interrupted, or need to finish the conversation quickly? Of course, you can’t write a script for every eventuality, but considering as many of them as possible will help make sure you don’t get blindsided and lose your cool. You might also want to find a trusted colleague with whom you can role-play some scenarios. Try different approaches, and test out phrases you might use for various possibilities. Then ask your role-play partner to give you feedback.