AA does not charge date and routing, PLUS Carriers change as long as the O/D city pair remains the same. On top of that, AA does not charge Upfare award type change. UA charges the Carriers change, AND the Upfare change.

Also UA's 21 days close in fee is charged regardless WHEN your ticket is issued. In other words, your ticket is issued on 5/15, with a travel date on 7/01 - Now it is 06/19, a whole month after the original ticket issuance date, but you now want to change the travel to 06/30 - you will be charged a fee by UA.

If the same situation is with an AA award, you will NOT be charged a fee because the proposed change date is well passed the 21 days from the date the ticket is issued.

BIG difference, especially when you consider that LH and LX premium cabin awards often dont become open until 1 to 2 weeks before departure.