Hi,

As much as possible, we can rewrite contacts using the Add/Remove Owners action located in the CDP-List of Contacts-Manage panel.
Here we select the contacts/tags of interest that we want to assign to the corresponding owner and perform the Add/Remove contact's Owner.

To complete the process just confirm with the button on the right at the top of the page Perform Action.
Also I attach the instruction: https://support.salesmanago.com/addremove-contact-owner/