At the start of this month (only noticed yesterday on Flyertalk) United made a big change to partner lounge access:
Beginning January 1, 2020, you’ll only be able to visit most of our partner lounges if you’re traveling in United Polaris® business class. Use the tool below to see where these lounges are located and if you can visit them on an upcoming trip.
Thankfully this does not affect Star Alliance lounges.
Hat tip to DDG
