If you’ve become accustomed to upgrading your domestic flights on United Airlines months in advance, the party will soon be over. The carrier is abandoning its current system of so-called confirmed upgrades in favor of the last-minute upgrades that are more popular in the U.S. industry.

United announced the change last week, although it’s not planning to implement it until spring. The current system apparently was confusing for some passengers, although I prefer to call it sophisticated and not at all difficult to master if you are a semi-frequent flier. However, that’s not why United is making the change. Rather, in trying to maximize revenue from selling first-class seats for cash, it will keep more of those seats open until just before departure…