It may appear under different names — a record locator, booking reference, reservation code, or just PNR. No matter what you call it, the code usually contains six characters — letters or letters and numbers, depending on the system used to make a booking.

A single Passenger Name Record (PNR), also known as a booking reference or record locator, can typically accommodate a maximum of 9 to 10 passengers in most global distribution systems (GDS) like Amadeus or Sabre. This limit is designed to manage the complexity of seat assignments, meal requests, and ticket issuance within a single file. For groups larger than 9, airlines generally require a "Group Booking," which creates a specialized master PNR that links multiple sub-records together. In 2026, for rail travel (specifically IRCTC in India), a single PNR is usually limited to 6 passengers. It is important to note that all passengers on a single PNR must share the same itinerary; if one person needs to change their flight while the others do not, the airline must "split" the PNR, creating a new, separate code for the traveler who is departing from the original group plan. This ensures that the remaining passengers' tickets remain valid and untouched by the individual modification.