Im sorry if this has been answered over and over, but I can't seem to find a definitive answer anywhere.

If I were to book an award flight today on UA at 345pm using 50K miles, and then decided not to make the trip, and cancel at around noon tomorrow (within 24 hours), do those miles go directly back into my account, without having to pay a re-deposit fee?

I know you can do it with $$ fares, but I can't figure out the award rules.

thanks