Go to TRIPS, rebooking, select the confirmed tickets, then cancel them. 1 month after they were issued, on the centre section of the TRIPS homepage, go to refunds and select the appropriate ticket - will refund into your payslip.
If you ALT has not been issued, it can take them a few days to do it. Request it online and then call staff travel and hold forever to speak to a real person who might issue it. Failing that it's probably a long wait at EGHQ!
A useful tip for ALTs, because it takes them so long to issue, when you are eligible, book one for a year in advance on some random date, then you can just use the rebooking option to bring it forward and change it as often as you like - instantly.