As per Southwest Cancellation Policy, Southwest Airlines allows you to cancel your reservation without penalty within 24 hours of making the reservation. Any cancellations made after this 24-hour period will be subject to a cancellation fee of $75 per person, unless the fare was purchased using a Southwest Rapid Rewards credit card, in which case there is no fee.
https://airtravelpolicy.com/southwest-airlines-cancellation-policy/
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