Sign into your Battlbox account, and then click the orange EDIT/VIEW button, then click the change subscription button. Select the new level you desire, and then press update subscription in the bottom right hand corner. Remember, this needs to be done no later than the 14th of each month or you will have to wait until the following box for the upgraded subscription level.
If you wish to upgrade for the month after the 15th. Then follow these steps above and then email email@example.com and the support team will finalize this request for you.