I booked a flight for 2 from O'Hara to Florence thru Swiss International Airlines. Originally I booked premium economy on flights operated by Swiss air. A few days later I was informed that the flights from O'Hare to Zurich and from Zurich to O'Hara were changed to flights operated by United Airlines. I decided to upgrade to polaris business on these flights. I was able to upgrade on the United Airlines site the flight from O'Hara to Zurich. I was unable to upgrade on the United site from Zurich to O'Hare. It kept giving me an error code. I called United and they told me only Swiss could upgrade me. I called Swiss and they told me only United could upgrade us. I'm paying with a credit card, not points and there are many open seats. The availability of business polaris seats was confirmed by both Swiss and United. This is our 52nd wedding anniversary and I know I should have booked business from the start however at the time i thought it was too expensive. Then I realized that this may be the last trip we take and we have always flown economy. Anyone have any ideas or experience with code share flights? I have talked to "supervisors" from both Swiss and United and they are "very sorry". Any help gratefully accepted.