How To Create an Admin Account
This will create an additional admin account with the password of 'test123':
zmprov ca email@example.com test123 zimbraIsAdminAccount TRUE
This will transform a normal existed user account into an admin account (in this example futur-admin will become an admin) :
zmprov ma firstname.lastname@example.org zimbraIsAdminAccount TRUE
To change the password run:
zmprov sp email@example.com NEW_PASSWORD
The admin account firstname.lastname@example.org was created during installation.