An angry customer can wreak havoc in the workplace. If you're busy trying to handle the upset customer, you can't help other people and you're likely to experience stress and frustration. On top of that, angry customers might not return to your workplace if they left unsatisfied. They might also leave negative feedback about your company. While you might be tempted to write off an angry customer, it is better to calm the customer down and keep her business by diffusing the situation.
Give Physical Signals
While it's tempting to match the customer's tone of voice, avoid it. If the customer is yelling, for example, make sure you lower your voice when you're talking. As long as you can stay calm, you'll send the customer a subconscious signal to remain calm, too. Your physical body language comes into play as well, so keep eye contact with the customer and give signs that you're clearing listening, such as nodding your head and staying quiet while he talks. The right physical cues give the customer the impression that you are taking his complaints seriously and will work to solve the problem, which helps to calm him down. Take notes to show you're actively documenting the problem.
Once the customer is done speaking, paraphrase his complaints back to him using your notes. You might want to pause before you speak to confirm he's done and give him a chance to deflate. Keep your tone calm and polite and make it clear you're doing this to confirm you have everything straight, but do not tell him to keep calm. Try to speak slower, at a rate of around 100 words each minute, to foster a calming effect. If you ask questions, try to stick to "Yes" and "No" questions, particularly questions with a "Yes" reply. Open-ended questions give the customer the opportunity to go on a tangent and get angry all over again.
Apologize and Inform
Even if you've done nothing wrong, offer the customer a sincere apology and reiterate you want to help. Don't pass the blame off on someone else, as this may inflame the situation further. The customer is more likely to calm down if he feels you understand the problem and truly want to help. If he feels you're not interested or aren't honest, he's likely to feel ignored and get more upset. Give the customer specific information about his problem so he feels he's being told the truth. For example, if you're working in a rental car agency and his car is delayed because of an accident, tell him about the accident.
Work on a Solution
Above all, the upset customer wants his problem addressed and resolved. You need to find out what you can do to make this happen. Work with the customer to find a solution that will fix his issue. If you're bound by company procedures, explain the procedures to the customer and try to find a workaround. It's important to stress you realize his problem is important and that you will do whatever you can to rectify it.