Originally Posted by
corporate-wage-slave
It certainly can't be done online. I have a feeling you can't call up either, since the ticketing structures are different between commercial and reward bookings.
Thank you. I booked an Avios redemption flight this morning and totally forgot I had an eVoucher I need to use. Was trying to figure out if I should cancel it within the 24-hour cooling-off period (and then try again using the eVoucher) but sounds like it won't work anyway.