If you would like to upgrade your account to a different membership level, simply log in to your account, then go to My Account > Account + Billing. Here you will find the Upgrade my membership button. On the following page, choose the subscription type you would like to switch to, and then if necessary enter or update your billing and credit card information. Then read and agree to the terms and conditions and click submit order. Any existing credit on your account will be prorated towards your upgrade.