Summarize this article:

Take a deep breath. Don’t take the other person’s anger personally. Instead, focus on keeping an emotional distance from them. Keep that intention in mind as this person acts out in anger. Avoid becoming agitated, raising your voice, or fighting with the person. Instead, actively think about skills you can use to help the other person regulate the situation enough to have a balanced conversation.   Remember that anger is always rooted in someone’s personal pain. It’s not about you, even if the person is taking out their feelings on you. You are not responsible for diffusing their anger. If they are not willing to work toward calm, disengage as soon as possible. People tend to mimic the behavior of those around them. Keeping calm may help the other person to slow or stop their anger. Even if the other person is shouting at you, respond to them as calmly as you can. If they are too worked up to communicate rationally, don’t say anything until they quiet down a little. If you raise your voice, you’ll only fuel the person’s anger. Don’t encourage them to fight. Saying something like “Settle down” or “Relax” will probably just make the person angrier. They may resent being told what to do and feel like you are brushing off their problem.  Create a connection with the person by acknowledging their anger instead. Say something like, “It seems like this is really bothering you. Can we talk about it?” or "I want to understand how you feel and I think that would be easier if we could talk instead of yelling." If you are in a public place, ask the person if there is somewhere you can go to work out the issue. If you feel nervous going on your own, ask someone along to act as a moderator and serve as your witness. When the person tells you what’s wrong, empathize with them. Make them feel like you’re on their side, even if you don’t agree with them. They will be less likely to turn violent if they feel understood. For instance, you might say something like, “So you’re hurt that no one told you about the change of plans ahead of time, is that right? You feel like no one wanted to include you.” Maintain an open, relaxed posture. Make eye contact with the angry person, but keep your expression non-confrontational. Don’t make animated gestures, put your hands on your hips, or fold your arms. Move slowly and calmly. Give the angry person plenty of space. This also gives you some protection if they do become violent.

Summary:
Stay calm. Keep your voice down. Avoid telling the person to calm down. Reflect the person’s feelings. Use non-threatening body language.