If it is within the 72 hour window and Delta has granted an exception (i.e., medical emergency, etc.), it has to go to a separate department for review and reinstatement. This process takes between 48 and 72 hours. Fees take longer for reimbursement - up to two weeks.

However, it looks like you are trying to extend out the award availability by booking, canceling, re-booking, correct?

In other words, you want to cancel and have the miles redeposited into your account to re-book the same award and have 24 hours to cancel again... I think this should be frowned upon, but in any event, you can only do this up until 72 hours out. At 72 hours, Delta will not allow you to cancel - I am not sure if the 24 hours to cancel applies during this period though. But they can see your history and can catch on quickly. I would not risk having your account suspended for this.