First thing, home area (or home directory) is created when you create a new user. In case if you have not created a home directory, then simply create it manually under /export/home and update the same in /etc/passwd file.
Code:
~$ cd /export/home
~$ mkdir username
~$ chown -R username:group username
username:......:/export/home/newname:/bin/bash
User username will then be able to use whole space allocated to /export/home mount point.
Second, in order to rename an existing home directory, simply rename the directory and update the same in /etc/passwd file.
Code:
~$ cd /export/home
~$ mv oldname newname
~$ vi /etc/passwd
username:......:/export/home/newname:/bin/bash
