Even if you find someone who might like to swap it could still be a little complicated. Assuming you don't find anybody your best bet is as soon as you get aboard go to the main restaurant and see the maitre d' and he should be able to sort you out, probably not for the first night but for the second and onward, it shouldn't be a problem. ... Neil.
Thank you for this - I was thinking of going to the Maitre d' but just thought it was worth a shot. I am sure it will get sorted. Roll on November 2nd!