The easiest thing is to call ! And sometimes they help you find the other ones
Unfortunately, that's no longer true.
While you used to be able to call and provide your credit card number to have a rep search for any travel funds associated with your name, you now must provide specific flight info, a confirmation number or a ticket number.
Applying Travel Funds: In the event your travel plans change and you need to apply travel funds to future trips, please make note of your confirmation number. Customers calling Southwest to request a refund or to research travel funds for a specific ticket must provide their confirmation number, ticket number or flight information (date, origin and destination).