Does NW have a similar policy as does UA, DL and CO where you can cancel any refundable or non-refundable ticket if purchased through NW, within 24 hours of ticketing for no charge?

If so, is this a publicized policy that is referenced to on nwa.com, or is it one of those policies that is invoked only if you asked a reservations agent? Lastly, are you able to process the refund on nwa.com?