Originally Posted by
notquiteaff
I wonder how the "for a day" actually works. I always thought that the alliances somehow share elite status data through a central database somewhere. If so, is AA going to send the status-for-a-day to that database and then revokes it the next day? (and how does it work with timezones). Will the AA membership card in the app temporarily change for a day to reflect the higher status? Or will it all only be in AA's computers? Also, if I am elite for a day, can I make seat selections for flights on future dates for free?

Ditto. The terms are very vague too. There is no mention of OW reciprocity. My guess would be isolated to AA.
RE seat selections, the terms say 4 seat coupons are awarded — expire shortly thereafter.
Maybe someone on FT has first or secondhand experience?
https://www.aa.com/i18n/aadvantage-p...conditions.jsp