First are you sure that you're not seated together ? The numbering system is weird but they really try to sit people next to each other.

Check https://www.tgv-lyria.com/ch/en/travelling/on-board/train-map

Thank you for the information, but I am sure we are not together. Close, But not together. I would also like to get to upper level.

In that case I suspect placing together may not have been possible anymore.

To see what's possible, contact the place where you booked.

You should be able to see a seating map on sncf-connect.com during the booking process. Afterwards as said contact Eurail or wherever you booked.

https://eurail.zendesk.com/hc/en-001/requests/new

Hi apologies for hijacking this thread but we are booked on the same service (other direction) in a few weeks time, we have Interrail passes and have bought our passholder reservations through the Eurail site (2nd class). I was a bit disappointed that we were allocated seats on the lower deck. Is there any way at all of getting reallocated to the upper deck?  According to this…

https://eurail.zendesk.com/hc/en-001/articles/11757617383581?input_string=changing+allocated+seats+for

it seems to suggest it might be possible to get them changed at a local ticket office, does anyone know whether this would be possible in one of the Paris stations? I’m guessing it might be worth a try anyway!

It’s worth a try, the ability and willingness of SNCF staff to be helpful varies a lot.

Please do report back to us if it has been successful or not.

Local ticket office happily did this for me earlier this year. As above, it depends on how helpful they are feeling but it should be possible.