Southwest Airlines change flight allows passengers free change with no additional fee charged. Given, the date or flight change must be at least 10 minutes prior to the departure time. Passengers of any fare including its non refundable tickets are valid for a change within the prescribed timeline. If Southwest cancels or changes the flight, then you are eligible to make changes in the flight up to 14 days starting from the date of issuance. Log in online with your booking confirmation number, First and last name to make the required changes.