About 3 years back I (then Gold) was travelling HKG-MNL in redemption J on the same PNR as my wife and her son. I was upgraded to F at the gate, at which point it would have created quite a delay in the boarding to try to reverse it, so I took it and then offered a seat swap to the person who was then in my previously allocated J seat. The cabin crew were fine with that and the person was quite a happy bunny since she had already been op-upped from Y!