Originally Posted by
ggomtel
I tried once and they told me that my fare didn’t allow it...
It depends what you ask for. You have two options really:
-Few days before your flight, you may receive a personal offer to upgrade to a higher class. I have received this offers on Avios bookings, although my experience is only on short-haul. I believe the bidding system is not in use any more, or at least it hasn´t been there on my last 15+ bookings.
-Upgrade at the airport: no idea.
Now if you want to upgrade a purchased fare with Avios, remember that ONLY flexible fares are suitable for upgrade with Avios in Iberia Plus.