Check availability before transferred Amex MR points.

UA likely has award availability that MX can't access. I don't know this for certain in this specific case, but I do know that different carriers often have access to different inventory in other contexts.

Try availability with ANA in addition to MX. They're a *A carrier as well.

If you can wait until US Airways redemption is all straightened out, you might try to get the UA flights w/ US miles (which you can get with your MR points).

Also, Air Tahiti Nui partners with American. You can redeem AA miles for flights to PPT. Of course, AA isn't a partner with MR. Does TN partner with anyone else?

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