When your two year contract term is completed, it is automatically changed to a month to month contract. There is nothing you need to do. Even if you wanted to start a new contract, that option was removed in January 2017. Purchasing a new phone requires you to purchase it at full retail price either outright or on the DPP agreement.
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.