How do I enable RPost as the admin for a user?

1) Find user and click on the Modify Access button.
2) Check the box that says Registered Mail to enable this for the user.

Upon activation or deactivation of this feature, you will see a pop up window that states that it will take 24 hours for the desired action to take place and once the account has been activated or deactivated an email will be sent to the admin to inform them of this action.