Upgrading to Economy Plus on United Flights booked with Singapore Miles
I am interested in a flight from EWR-MSY in December. I have the Ritz card and would use the $300 from it to upgrade 2 seats, but I would be booking it with Singapore miles (expiring so need to use them up). Does anyone know if you can book a flight with Singapore miles, then login to your reservation on United and still be given the option to upgrade to economy plus. I know AA lets you do this if using other miles, while Delta does not, but have never flown United booked on Singapore before so wasn't sure how it worked or the approximate cost. Thank you.