Originally Posted by
YYT82
When you retain the credit to rebook later, you also retain the PNR and its creation date, which is why the promo code would still be attached and the discount still applies. You would only need to ensure you are not booking outside the travel period or inside the blackout period stipulated by the said discount code.
I guess the only downside would be if the new ticket is less than the cancelled one, the excess amount is forfeit