Don't know when your annual fee will hit next -- I'm guessing soon, hence this post -- but if you have a little time, you might as well wait it out. Amex's relationship with CO is ending but they may add UA as a partner which would get you *A miles. Note also, re a previous post, that Chase claims to have 1:1 transfers to "leading airlines" but once they, too, drop CO, they won't have any US carriers. (They, too, might add UA; again, this all remains to be seen.)