I called Adobe to have my address changed from the USA to the UK. The agent said this would have to be done by canceling the USA account and opening a new account in the UK. He had me create a new email address for the new account.
Now I have a new paid account in the UK but my assets are trapped in the old USA account, which is now a free account. The new UK account cannot see any of these assets.
After chat sessions with multiple agents, it appears that no one knows how to sync files in my old iCloud drive to iCloud drive in my new account. Regarding Lightroom, I was pointed to an app called lightroom-downloader and told to download all my photos from the old account and re-upload them to the new account. With 225 GB of photos, I think this would take quite a while, so I have not tried it.
I am posting this to complain about the terrible customer service and to warn other users that it is dangerous to ask for a change of address to another country. It may cause loss of cloud data.
iCloud is nothing to do with Adobe. But I guess you mean Creative Cloud. Can't you just re-upload your local backup copies of all the files, rather than try to do the (impossible) Cloud to Cloud transfer?