Qatar Airways reward booking – upgrading class when seats open up

[Aston100]

Qatar Airways.
If I use Avios to book one-way economy flights and then some time later business class reward availability becomes available on one or both legs of the journey, does anyone know how I would go about trying to change the booking (economy reward seats to business/first reward seats)? Is it easier to just book the new business/first seats and cancel the economy seats after?
Would I be liable to pay an admin/change fee, and what does it look like? (I know it is $25 to cancel an economy reward seat up to the day before departure).

Assuming seats are still available for cash in a higher cabin, is it possible to pay at a UK airport on the day of travel to upgrade reward bookings?

Thanks.

[phantomchickenz]

I’ve just had to do similar. You can’t change the reward booking to a different class, you need to book a brand new one and cancel the old one (with the accompanying fee, I think it was £35pp). Avios refunded immediately, cash takes time.

Not sure about cash upgrades.

[harley]

Yes as phantom mentions annoyingly you cant change, i also tried. You have to cancel and rebook. Qatar fee is slightly lower if you booked via them i think it might be the $25 you mention, ba is standard £35