Originally Posted by
The Saint
Don't bother asking the person in 1K whether s/he would like to swap for 5K.
Why would a, presumably solo, traveller rather be in 1K near to a stranger than in 5K in much more privacy?
To the OP, here's a slightly naughty way to get your partner into 1K. Upon boarding have a big coughing and spluttering fit. Sniffle a lot too.
Then ask 1K if they'll swap with 5K. The existing 1K pax will jump to 5K quicker than you can imagine.