Airport Control means the Airline Ticket Counter and Gate takes ownership of the reservation 24 hours prior to departure to allow for any changes and for online checkin. You could essentially call the airline directly to change your return date now that its within 24 hours of your first flight(unless the return portion stays with the travel agent until 24 hours prior to the return).

The airport agents could also rebook you if there are any delays and the reservation becomes unlocked from the Travel Agent. Hence this is the reason why you may not be able to access your reservation online if it was booked by a travel agency as they may have booked you as part of a group rate and its a conflict of interest for the client to deal with the airline when they should be dealing directly with their travel agent.

Hence this is the reason why there is an option for Travel Agents to be transferred to a special department within the airline who handles these special reservations. Sometimes they are booked under Group Fares/Bulk Fares and come with special restrictions like no advanced seat assignments until 24 hours prior to the flight when then it gets released for online checkin/seat assignments etc.

I once had to change a Lufthansa Reservation booked by a Third Party and once I flew the outbound portion I could call Lufthansa and they were able to change my flight for just the change fee thus avoiding any additional fees added by the Third Party for a reticket.


Once you are within 24 hours before your flight for the most part you can contact the airline to do any changes etc.

I hope this helps and I'm sure others will "chime in" too.