Originally Posted by OperaLover

I want to report back my success using the United MileagePlus miles to upgrade the EVA Airline economy tickets to business class. As already been explained by this thread, I first searched for EVA Air JFK-TPE-JFK flights through United Airline's award travel search page. I found the flights I wanted showing saver business award available for both flights, and the system confirmed the fare class was I. I then went to EVA Air's website to book the economy class tickets. Only the Eco Flex option gave me the class B tickets. The other options were all cheaper but not class B or Y tickets. Before I booked, I also called EVA just to check. The agent told me to make sure to book class B or Y, and she said the online price quote is usually cheaper than booking through the phone. She also told me that she cannot confirm whether these seats can be upgraded because the upgrade is handled by United. But since I am booking far in advance (booking in May for October flights), and my departure city is in the US, I can cancel with full refund within 24 hours. I went ahead and booked the class B economy tickets on EVA Air website. Within 10 minutes I went to the United SAUA request website and provided the ticket information. My upgrade was confirmed immediately. I went back to EVA's website to manage my reservation, and the ticket was now showing Royal Laurel Class Z.

Thanks all again for documenting this upgrade method!