Abstract: A first itinerary comprising a first plurality of first location elements associated with locations to be visited during a trip, each first location element comprising first duration information, first arrival date information, and first departure date information, is maintained. A second itinerary comprising a plurality of transport elements associated with transportation to be used during the trip and a second plurality of second location elements, each second location element associated with a corresponding first location element, each second location element comprising second duration information, second arrival date information, and second departure date information is maintained. Modification information indicating that a duration specified in a selected first location element has been altered is received. A first duration, first arrival date information, or first departure date information in a first location element is adjusted based on the modification information.