Kopia repos are “self-contained”. As long as you don’t change the underlying filesystem, e.g. move from local fs to S3, you can simply copy the whole repo anywhere else and use your client to connect to that repo. All you need to do is to “Connect to new repo” in Kopia UI and remove the old one.
Note, that you’ll need your repo password for that, but that should be kept safe anyway.
Ad password: solved. After “sync to sftp” the password of the target repository is the same as the password of the source repository! So the password of the “repository create sftp” step is gone then.
As soon as you understand that, it’s clear. But it took me a while. Might be worth mentioning somewhere in the docs (maybe it is mentioned, I don’t remember reading this).