Originally Posted by vintagepilot

I don't think that is the case. We had a 241 trip planned and paid for but then changed it 6 months or so later when F became available. This ended up being a cancel and re-book, which I hadn't really thought through, as by then the card which earned the original voucher, and had paid the taxes, had been closed. It all worked - the taxes, points and voucher came back, we used it for the new booking and paid the new taxes with a new (Amex) card. The only hiccup was having to call amex to get the refund, which had been applied to a closed card, transferred across to an existing card.

I've just done a dummy 241 booking - the payment page defaults to my saved cards (strange, none of which is the 241 earning card - must fix that) and also gives the option to use a new card. So, I think the only stipulation is that you use an Amex to pay for 241 bookings.