Confirmable Suite Upgrade question

No idea but since you need to call anyway to use it that would get you the quickest answer.

If you don’t get anywhere you may want to ask if they can convert it to F&B credits or points. I tried and was unsuccessful using a CSU (again) recently that was getting close to expiry. As a “one-time” offer they agreed to the swap.

I understand there are restrictions on their usage, but if they become difficult to use in practice, then people get fed up. The worst thing for me was the wasted time keep calling up and trying to use them only to be told there was no availability and half the time the agents didn’t know the underlying rules anyway so you knew it was unlikely to go anywhere