Moving all mail from one user to another

Hi all

I have a user that has changed domain, and I am looking to move all her mail from her old account into her new one, but I am really unsure about how to go about it

I would think that I am should use https://doc.dovecot.org/main/core/man/doveadm-move.1.html to do it, but the example supplied and all discussion about that tool I can find online is only about moving a users mail across folders on their account, and not the entire accounts content to another account.

Has anyone tried to do something like this?

-- Peter Reinhold