Gather your reservation information and frequent flyer number if you have one. You should have either a confirmation or reservation number for your ticket, and you'll need this when you log in to the airline's website.
Log in to the airline website or the online booking service you used when making the reservation. If you do not have an online account with the airline, you will be asked to register. Once you are logged in you will be able to see your personal information and proceed with the seat changing process.
Access the itinerary for the flight on which you'd like to change your seat. With some airline websites, your future itineraries will be visible as soon as you log in. Others may require you to enter your confirmation or reservation number for a particular flight.
Once you have accessed your itinerary, you will see your current seat assignment. Most airlines and booking services have an option marked "change seat assignment" or "view seat assignment" which will open up a view of the plane's layout showing seats that are occupied or available.
Change your seat by clicking on another available seat. Bear in mind that some airlines do charge an additional fee for some seats, such as exit rows. Once you have chosen your new seat assignment, save your selection. Print out a copy of your itinerary with your new seat assignment.
