How to move contacts between lists
If you'd like to move your subscribers from List A to List B, you'd have to do that manually. First, export your subscribers from List A. You can export all your subscribed contacts at once or manually select the contacts you'd like to include in the export.
Once your contacts are exported, you can re-import them into List B.
To bulk unsubscribe from List A, go to "Add contacts", click on "Import contacts from a file", and then select Unsubscribed and Update existing contacts. Finally, click and select the list of contacts that you've just uploaded to List B and click on Next.