Initially it came into existence when airline passengers needed details of more that one destination and hence the PNR was quoted for easier reference from travel agents across the country or across the world.

To get a PNR number basic details of the passenger are requested at any travel terminal, be it the airways or railways.

a) name of the passenger
b) contacts of the travel agent
c) ticket details
d) one itinerary segment of the travel
e) name of the passenger making the booking.
Once these details are given the Computer issues a unique alpha-numeric record locator, which remains unchanged whatever changes or alterations done to the travel plan.

Hence as a passenger if you need any details or any further assistance with your itinerary, you have to quote your PNR number and your details will flash before the travel agent.

Besides the above details it has now gotten mandatory to get more details of the passenger in lieu with the anti-social elements.

For instance
a) any restrictions on the ticket
b) the form of payment made
c) thorough details of contact and residential address of the passenger
d) age details especially in case of minors or senior citizens
e) Special Service Request (SSR) if the passenger has any preference with seating or meals to be served
f) ‘Other Special Instructions’ this is incase the passenger needs something special from the travel mode which should be kept ready.

Hence overall the PNR status is very helpful to the passenger traveling and to the travel agency. So that there is smooth flow of information and the traveller does not face any hiccups while traveling.