I missed the return leg of an award travel from OGG to EWR (3 segments) by one day -- I just lost track of time (blonde moment). It was a bit embarrassing when I tried to check in on the wrong day. However, when I called the CO elite desk a very nice agent noted that the miles for the missed legs had been re-deposited and she rebooked me on the exact same flights (first class) on the next day's flghts. No penalties. It required supervisor approval, but she treated it as a missed flight. Perhaps 1K status helped here, but it took 20 minutes and the CO agent was very helpful.