Hi,

yes, try checking with them direct. Check your class of ticket. There are various class of ticket also and depends on the new date that you choose if it is available.

If available usually it will not exceed QR150. But if you need to change class meaning you might have to top-up some difference to the class. Example you are in Y-class so no more space and available is C-class, then you may have to top up for normal ticket for one sector/way. Cn be as much as QR900 if the time and date is peak.

Good luck.