Article: . This is usually fairly easy to do: if you bought your phone from a carrier (e.g., Verizon), the phone is probably locked to that carrier's network unless you bought the phone without paying for a contract. However, if you bought the phone online without a specific carrier included, the phone is most likely unlocked. Most carriers have specific rules about when you can approach them for an unlock code, but the general rules usually include the following:  You must have owned the phone for at least 6 months. The phone must be entirely paid off (e.g., you aren't making monthly payments). The phone must not be blacklisted or reported as stolen. Any contract you had with the carrier must be up. Not all phone networks are compatible with each other, so call the company to which you want to transfer and ask if your phone will be compatible with them once you switch from your current carrier. In most cases, you'll be able to use your phone's LTE SIM slot to make it compatible with any other LTE-supported carrier. You can buy a SIM card directly from the carrier, or you can buy one online to save a few bucks. Once you have the SIM card for the carrier you want to use, you can proceed.

What is a summary?
Ensure that your phone is actually locked Determine whether or not you meet your carrier's unlock criteria. Make sure that your phone will work with your preferred network. Buy a SIM card for your preferred network.