i got to MEX and am throwing away this ticket, unless someone with better fare rules knowledge than me has any tips on cancelling. some unforeseen issues back at home, it'll be a lot cheaper for me in the long run to just head home now.
for anyone interested in upgrades on AM, you might check out optiontown. mine cleared from TIJ the day before at around 30 bucks. luckily hadn't purchased yet for the two flights on this ticket. some forums say bad things about them, so buyer beware. i definitely wouldn't buy it months or even weeks in advance and float them the ca$h.
also MEX is a decent stop for the various ruins and museums. there is a Hampton for 10K points a night that is central and pretty nice that I stayed at.
PM me if you want to know anything else on my limited MEX and optiontown experience.