Originally Posted by
Johnnieboy
You could also try amending them through the Finnair website. Enter your PNR in the manage my booking section. I have changed my ffp number there many times, including earlier today after making a BA Avios booking and switching to my QR number. Might not work for both of you but worth a try.
Last month I had to resort to Finnair to fix a similar situation to OP (multiple passengers having same FFP; actually my FFP even though I wasn’t even travelling)