Originally Posted by
myrkyllinen
I have this question because when someone notices some mistake on his/her booking, many times one phones the airline and they issue an OSI which tells check-in people "please change whatever on the passenger info". I just thought that why do they issue the OSI instead of changing it themselves
Depends on what kind of change...but, I suspect most changes require some form of id verification from the passenger. Anyone can pick up a phone and try and change your itinerary or name or whatever on your PNR. There are probably security reasons for the need to have someone physically verify your identity and make the change in person.
-L