I usually want to print my boarding pass in advance, and then make a change to fly standby if conditions change. Twice now I have printed my original boarding pass, and the OLCI won't allow a change to an earlier flight. Like the previous poster, I just went to the airport and made it on the flights I wanted anyway. However, it is nice to know for certain in some instances, and peace of mind would be worth $25.

Another thing, it would be nice if not only the OLCI allowed changes after printing a boarding pass, but also did an upgrade to R when available.

Just in case someone thinks the issue exists because NW does not want you printing out more than one boarding pass, please note that you CAN print out additional copies of the original boarding pass at two separate times.