Your English is pretty good, so I'll assume you are in the U.S. With a lack of details on your question, assumptions have to be made. There are a million carriers, each is different. If you are on T-mobile, call customer service and just request it. They will oblige with an email, usually within 24 hours(they tell you up to 7 days) with the unlock code, and instructions on how to unlock it. If you are on ATT, it's a little trickier. You will have to call customer care and lie to them. Here is what to tell them. You are traveling out of the country in three weeks. If they ask where, say Singapore or Thailand or something in Asia. Tell them you don't want to use their services while out of the country, and that you will be purchasing a pre-paid SIM card upon your arrival there. They can't argue with you that way, it's in their policy. They will create a case, send it to tech support and they will tell you that it will take a few days before you receive an email from tech with the unlock code and instructions. There is another way, you can pay for it third party. I would go with one of the first options, being that they are free. Good luck.