Summarize this article in one sentence.
If you suspect someone has run away, call 911 immediately. You do not need to wait 24 hours to file a missing person report on a child under eighteen. If you are a friend of the runaway, contact the parents first and let them know your suspicions. If you are concerned that your friend ran away from an abusive situation at home, or the parents seem uninterested in locating their child, call the police yourself (or have your parents do it). Runaway teenagers can quickly find themselves in dangerous situations, so it is important you act on your suspicions. Give the police a detailed description of the person. Indicate height, weight, hair and eye color, if they have glasses or braces, any distinguishing marks, and the last clothes they were seen wearing, as well as other identifying information. For example, you could say, "Jane is sixteen years old. She's about 5'7" and 130 lbs. She has short brown hair, brown eyes, and a mole next to her right eye. She wears glasses for reading. She likes to dye her hair, so it may also be a bright color. She was last seen wearing a red tank top, black shorts, and black flip flops. She often wears a gold necklace with a cross." Ask the police to make a report to the FBI's National Crime Information Center database, known as NCIC. In order for a missing person poster to be created and disseminated to law enforcement, you need your child's information entered into this database. Ask which officer will be assigned to your child's case when you are making your initial police report. Record the officer's information and the best way to contact them. After you have filed your initial police report, begin making calls to other organizations that can help you in the search for the runaway. Besides these organizations, your local police may have additional resources for you to contact: Call your Sheriff's Department and state police to report the runaway. Call the National Center for Missing and Exploited Children. Call NCMEC at 800-THE-LOST (800-843-5678) after you talk to your local police. They will help coordinate leads to your local police. The National Runaway Safeline can provide assistance and support in this situation. Call 800-RUNAWAY (800-786-2929). They can leave your message for your child, should your child get in touch with them. Additionally, they can help your child get in touch with you, and help mediate parent-child disputes if needed. When calling other agencies, indicate what you have already done. For example, you could say, "I have already spoken to Officer Jones in my local police department, who took the police report and is assigned to the case. Is there anything else you recommend I do, or anyone else I should talk to?" Keep a notebook handy and record all conversations and phone calls, with dates, times, and topics discussed. This will help jog your memory and keep you organized. Things will be moving very quickly, and you will likely not be able to remember details of conversations, or if you talked to a certain person. Get in the habit of writing everything down right away.

Summary:
Call the police. Call other law enforcement agencies and missing child clearinghouses. Write everything down.