Originally Posted by
nialltom
I’m having trouble finding domestic availability on partner programs of either American or United, to use Amex MR. I can find availability directly using Amex Travel, but at premium point cost. I checked Avianca and a few other partner sites but they are showing very little availability. Travel is from ORD to MIA. Any suggestions on how to use MR for domestic travel on these airlines for this route?
Be aware that the domestic flights on these airlines are priced "dynamically". When they are their lowest level (eg, around 25000 miles RT domestic economy), you can typically see the flights on partners sites. When you can't see the flights on partners sites, they are often
way way more expensive with that airline's one miles (often 100000 miles or even much much more!).
So be careful what you wish for.
However, to answer your posed question, as
friedablass pointed out, you can transfer MR to Marriott Bonvoy, and then transfer Marriott Bonvoy to AA or UA. Of course, doing a two-transfer may not always give quite as good a value as a one-step transfer, but it is possible.