Now I know this questions seems like it should have an obvious answer of no, so I am sorry if it comes off as rather thoughtless -- but there are always those situations where the obvious is not always the answer.

I booked two tickets on JAL about two weeks ago from LAX to NRT only because the price was half that of AA. Right now, the AA price is exactly the same as what I paid for JAL. Is there any way I can switch the tickets over to AA? I booked the tickets as a JAL flight number, through JAL.COM.

Would like to use AA for obvious reasons of mileage accumulation, and upgradeability.