Hey @Sean_72852 , Welcome to the 3Community 🙂
If you are within 60 days of the end of your minimum term then you will be able to upgrade to your current plan or you can also decide to increase your tariff and your new 24 month contract will start at the end of your current minimum term.
If you are currently in contract and you have not reached your upgrade date then moving to a new tariff won't allow you to upgrade as part of your contract.