I don't use this benefit often and am confused how it works if you have an early flight (say noon) and you wanted to push back to the last flight of the day? I have SEA-SMF in discounted F for noon and really need to knock back some work during the day and help get my kids down in the evening now and wanted to grab a seat on the 9:15pm flight. Under the "six hours prior" to my desired new flight, I am essentially no showing on my ticketed flight, so SOL if there are no seats left at 3:15pm for the 9:15pm. And I don't care about F, will gladly sit in the back of the bus if that gets me on the later flight.