Once my friend and I were flying IAH-ORD-PHL on UA, and there was weather in ORD, and our flight to PHL was cancelled. Sure enough, a GINORMOUS line formed. We decided to seek out someone less busy, who got me confirmed on a US Airways flight out the next morning, and put him on standby (?) for the flight even though there were seats available.
So, we then went down to the US Airways baggage office to sort it out, and thankfully, the nice lady there used to work in ticketing, and changed my friend's reservation to confirmed.