The free change policy of Change Southwest Flight states that there are no additional fees for passengers. Given that the date or flight must be changed, it must do so at least ten minutes prior to the departure time. Passengers may alter their itinerary within the allotted time frame regardless of the fare, including non-refundable tickets. You have up to 14 days from the date of issuance to make changes if Southwest cancels or modifies the flight.Log in online using your reservation confirmation number, first and last name to make the necessary changes.