In order for you to change/add/delete an administrator in RDB you need to:
Double-click on the RDB Pronet icon on the screen.
On the Ribbon, click Options and then select Manager.
Choose the user maintenance option.
Select the user.
Click the Role tab at the bottom of the window.
If the user has been assigned a role it will appear in the list.
To delete a role click on the role once and press the delete button on the right.
To add a role click the Add button and a list with available roles will appear.
Select the role you want to assign to the selected user, Click select and OK.
When you are done click Save and Close the user maintenance window.
The user might need to restart their RDB Pronet in order for this changes to activate.