Only those cancellations received at the NAA Operations Center by mail, e-mail, telephone, or fax on or before May 4, 2018 will be entitled to full refunds of the conference registration fee.  Cancellations between May 5, 2018 and May 19, 2018 will be subject to a $100 cancellation fee.  No refunds will be granted after May 20, 2018.