The sethostname Command

oldname.example.com> sethostname
[oldname.example.com]> mail3.example.com
oldname.example.com> 

For the hostname change to take effect, you must enter the commit command. After you have successfully committed the hostname change, the new name appears in the CLI prompt:

oldname.example.com> commit
Please enter some comments describing your changes:
[]> Changed System Hostname
Changes committed: Mon Jan 04 12:00:01 2010

The new hostname appears in the prompt as follows: mail3.example.com>