Thought I should post this here for people's benefit as I didn't see this anywhere:
A list of 24 hour award cancellation policies.
The good news is that most major airlines currently allow award tickets to be cancelled within 24 hours after booking. But it’s not universal, so I’ve gone ahead and put together a chart of the current 24 hour award cancellation policies for many of the major U.S. airlines.
IMPORTANT NOTE: In most cases, you must book your award ticket at least 7 days before departure to be eligible for these 24 hour policies.
Airline Award Cancellation Policy
Alaska Allows 24 hour cancellation of award tickets without a fee.
American Does not allow 24 hour cancellations on either revenue or award tickets without a fee.
British Airways Allows cancellation of award tickets without a fee up until 24 hours before departure (but you do forfeit the taxes).
Delta Allows 24 hour cancellation of award tickets without a fee.
Frontier Allows 24 hour cancellation of award tickets without a fee.
Hawaiian Allows 24 hour cancellation of award tickets without a fee.
JetBlue Allows 24 hour cancellation of award tickets without a fee.
Southwest Allows cancellation of award tickets without a fee at any time.
Spirit Allows 24 hour cancellation of award tickets without a fee.
Virgin America Allows 24 hour cancellation of award tickets without a fee.
United Allows 24 hour cancellation of award tickets without a fee.
HT: FM