You want to be able to add another administrator account to the command line interface (CLI) of the Symantec Messaging Gateway (SMG)
You want to remove the existing administrator account in CLI
By design, the only account that is available to end users via CLI is the initial administrator (admin) account. SMG is hardened to prevent others from accessing functions, apart from the system administrator. The admin account via CLI cannot be changed, nor removed.
Other administration accounts can be added via GUI to administer functions within the Control Center, but not via CLI.