Back in prehistory before upgrades were automated and even before there were FF programs, a passenger's PNR could be flagged as inconvenienced/IROPed by any agent and a supervisor could flag it as mishandled (usually meaning that some employee had really screwed up or behaved very badly), which was more significant and often meant an upgrade if a FC seat was available, implicitly with priority ahead of anyone else. If lots of FC were available, you would get the FC boarding pass early but if not, the upgrade would be handled at the gate. This is what several legacies did back them, although I don't specifically remember DL's procedures for inconvenienced and mishandlled passengers, which were official designations.