Please contact the vendor or travel agency from whom you purchased your reservation. TripCase is a tool that helps you organize your travel and display your itinerary and travel documents. TripCase is not a booking engine; therefore TripCase is not able to make changes to your reservation.
You cannot change your seat assignments on TripCase.
You can view your seat or see what else is available from the Seat Maps tool, but you must contact the airline or your travel agent to make any changes.