How to remove personal retention tags from all users mailboxes programmatically

My customer is using MRM and has been for a long time in office 365.  Recently they noticed that employees were putting personal tags on some items, this is against their policy.  The way to prevent users from using personal tags is documented here.
Users can use all personal retention tags regardless of retention policy in Exchange Online - Microsoft Support

Once that is complete, they'd like to remove any personal tags on email items or folders in all user mailboxes.  I am told you need an EWS script to do this.  Does anyone have an examples script?