Upgrading Award Seats on AS/AA flights SEA-SCL
Asking for my brother.
They have 2 RT tickets for 45K each using AS miles on a flights from Seattle to SCL ( Santiago Chile) with a connection in Dallas. ( flight to Dallas on AS) They are presently booked in coach.
Any options to using additional miles or cash to upgrade to Premium coach on the Dallas to Santiago flight? Who would they call? AA?
Thanks.