Currently the User Management page only gives the option to “Transfer Ownership of another user’s assets such as reports, dashboards, filters, and so on”, if the user is not an admin.
There is no option for one admin to take ownership of the content of another admin. Perhaps this can be done with a support ticket to request the content ownership transferred but this is not outlined in the documentation.
I would love to see this as part of a larger content management tool that could do more detailed transfers of ownership rather than the instigating user simply being able to take all content to themselves.
If you are referring to only admins being able to transfer ownership and only to themselves, see my recent idea: