Originally Posted by
Passmethesickbag
I guess you could get DL to match you, deal with a year of connecting flights, and then get UA to match you when you've earned top-tier status on DL.
Ugh. But then those SkyPesos will be orphaned.
There really is no good way - *A rules don't permit this.
I would recommend this:
November 1st - December 31st - Credit to AC, or until you hit some milestone of redeemable miles.
January 1st onwards - Credit to UA. I don't think SHARES will let you credit to UA while using the benefits of AC, but at check-in, show your AC card (free luggage) and at the lounge (free lounge access for non-US-based *G on all flights). Both are YMMV, of course. Best you can do for now...