Login to Your Zimbra Server with root login and password .

Type following commands :-

[[email protected]]# su – zimbra

This Command will change the Console name to

[[email protected] ~]$

Then Type Following command.

[[email protected] ~]$ zmprov -l renamedomain olddomain.com newdomain.com

This has been tested against Zimbra 6, 7 and 8.

Reference: https://communities.vmware.com/thread/459923