At the bottom of the appliance Welcome screen (with blue background), there is a menu item with the choices "Login", "Configure Network", and "Set Timezone". Login into the virtual appliance root shell by selecting "Login", then log in with the username "root" and the current root password. At the shell prompt ("#"), type:
You will then be prompted to enter a password and confirmation.
Enter new UNIX password:
Retype new UNIX password:
After you return to the "#" prompt, you can type "exit" to log out (and return to the Welcome screen).