According to JetBlue refund policy, passengers may be required to pay cancellation fees of up to $200. The balance will be given as a future use travel credit.
With the exception of basic blue, JetBlue doesn't charge a cost for modifying or cancelling a ticket. The price may change depending on the flight route you choose.
There is a flat price of $75 per person when you apply for standby, and the traveller is not responsible for any fare differences.
Also check : Southwest refund policy