How do I move knowledge to another sub account?
On the knowledge library (listing) page, as you view your content, you can see the account (or sub-account) to which records belong. Select the checkbox next to a record (or multiple records) to move the selected content to a specific sub-account.

Once you have selected knowledge records, select the account or sub-account that you wish to move the knowledge to and click "Move these Knowledge items".

Keep in mind that if you move content, you may impact the visibility others have to that content.