Summarize this article:

One tried and true approach to dealing with racists is not dealing with them. Don’t give the person any of more of your attention. Keep walking, working, or doing whatever you were doing. They’ll get the message. While some people make racist remarks simply out of ignorance, others do so out of hatred. If at any time you don’t feel safe around a racist, ignoring them is the best bet. Don’t say anything. Get yourself to a safe place where others are present, such as a restaurant or public building. If a racial remark happens at your school or work, you can tell someone in charge. This ensures that others in authority are aware of potential racists. It also helps you create a record of the incident in case there are issues in the future.  You might go to a teacher, guidance counselor, or supervisor and say, "I was called a racist name and I'd like to report it." Tell the person, in detail, what happened. Keep in mind that they may not do anything about the initial incident. But, be sure to report any further incidences to them. If they don't act, reach out to someone else in charge, such as their supervisor. If the person who called you a racist name is someone in authority (such as an employer, business owner, or teacher), you may need to take legal action due to discrimination.

Summary:
Ignore them and their comment. Get to a safe place. Report them to a superior. Know when to take legal action.