Update 20 November 2023:

It is now possible to re-enable centralized user management in some organisations. Please create a Support Ticket with us and we can check if it's possible for your organisation. There are a few requirements before we can migrate your org to use centralized user management:

• You cannot migrate users with the Trusted role as that role does not exist in the centralized user management model. You will need to remove the Trusted role from any users that have it.
• All site admins need to be made org admins (or demoted to normal users) as the site admin concept does not exist in the centralized user management model.
• You need to remove all sandboxes.

Problem

At the moment there is no option to enable centralized user management once disabled.

Suggested Solution

Option to enable centralized user management once disabled 

Why This Is Important

At the moment transfer of products from one Org to another Org is not possible if centralized user management is enabled in either of the Orgs therefore, we need to disable centralized user management in order to proceed with the product transfer. 

We need an option to re-enable centralized user management once the transfer is complete.

Workaround

For this issue, we recommend creating a Support Ticket with us and we can check if it's possible to re-enable centralized user management on your org.