Visit the Alaska Airlines website at Alaskaairlines.com. Scroll over the "Mileage" tab and then down to "Show All" and select. You will be directed to a page titled "Mileage Plan."
Click "Mileage Q & A" located under the "About Mileage Plan" menu on the left-hand side of the screen.
Click "Awards" under "Mileage Q & A" and on the following screen titled "Awards Q & A" click "Can I Change My Awards Reservation?" You will see the following message, "To make changes to select award reservations on Alaska Airlines/Horizon Air and Mileage Plan Partner flights, use alaskaair.com®."
Clicking on "Use Alaskaair.com®" will direct you to the "View/Change a Flight Reservation" screen.
In the box labeled "Traveler's LAST Name" input the last name of the ticket holder. In the box labeled "Code or Number" enter the ticket confirmation code or the e-ticket number and click "Continue." You'll be directed to a screen where you can view your existing reservation, change dates or times (see Tips for restrictions), change seating assignments or cancel your reservation altogether.
