For the most part, Cokacola14 is right. However, before proceeding with his steps, you should check if the phone is unlocked or not. To do this, you'll need a SIM card for a different network, like AT&T. Borrow a friends or family members and insert it into the phone. If the phone is unlocked, it will function as normal. If it is locked however, the phone will not work and will simply prompt you to enter the unlocking code.
This code can and will only be provided by Verizon at the end of your contract, if you are on one. If you are not, they should provide this code to you for a small fee - likely between ten and twenty dollars.
If you are on a contract and wish to end it prematurely, be aware that this comes with steep penalties...