1. An apparatus for updating one or more databases modified by a first re-accommodation, the apparatus comprising: one or more processors; and a memory coupled to the one or more processors, the memory storing a plurality of data structures comprising a first database of reports, a second database of passenger name records, and program code that, when executed by at least one of the one or more processors, causes the apparatus to: receive a first request to execute a second re-accommodation that modifies the first re-accommodation; in response to receiving the first request, retrieve a report associated with the first re-accommodation from the first database, the report including a record locator that identifies a passenger name record modified by the first re-accommodation and an identifier that identifies a first envelope of a plurality of envelopes comprising a history file of the passenger name record; identify, based on the record locator, the passenger name record in the second database, the passenger name record being in a first state that represents a current status of the passenger name record; identify, based on the identifier, a portion of the history file corresponding to a modification made to the passenger name record by the first re-accommodation; determine, based on the portion of the history file, a second state of the passenger name record that represents a first previous status of the passenger name record before the first re-accommodation; determine, based on the first request, a third state of the passenger name record that represents a desired status of the passenger name record after execution of the second re-accommodation; and modify, based on the second state, the passenger name record from the first state to the third state.