Power Pass options and upgrading in park

Hi. New to the Universal Orlando resort and staying at the HRH from 10/31 - 11/6. I can get e-tickets from our American Express points but the only option is a 2 day ticket. Would I be able to upgrade to a season pass from a 2 day e-ticket? We have 6 full days and planning on visiting Sea World one day and going to the Kennedy Space Center another day. Thanks for any input. Not planning on visiting any WDW parks on this trip - unless I cave.