Reward Flights

Can anyone please explain to me if I can upgrade reward flights, and if I can how it works. the T&Cs are a bit confusing.

Thanks

If you booked your reward flight with pure miles, then as long as there is reward availability for an upgrade, you can do it at any time. Call FC, it's really easy. There will likely be additional tax to pay.

For example, if you have a PE reward to the US for 60k miles spent, an additional 40k miles will get you in Upper Class.

I don't know - but would guess - that upgrading from the 'sale' economy rewards at the moment, would be to the full amount for the cabin you want. So not the difference between say Y at 40k miles and PE at 60k, but rather an additional 35k???

If you booked miles+money then no, you cannot upgrade.

Nor can you upgrade a reward flight with cash.