It's over, apparently
I spoke to a representative from AGR not long ago after I could not find the link to transfer to UA.
She told me they had received an e-mail earlier today stating that the partnership was over, effective immediately.
I guess I am out of luck. I had obtained the Amtrak MasterCard and had planned ot transfer points into UA, but never did. I wish they had given some notice. Perhaps I did not look in the newsletters, but was this announced anywhere? On the website, in one place it says it is a redemption option, but when you go to that page, only Continental and Midwest are listed.