1. Do a controlled shutdown/reboot on the VCSA appliance.
2. At the time of boot, hit the "E" key several times until you see the boot loader screen.
3. Add the text "rw init=/bin/bash" to the end of the first line (starting with Linux) and then hit F10 to continue to boot (see image below).
   
4. Once booted, type "mount -o remount,rw /" and hit enter.  This will reload the root partition in read-write mode.
   
5. Type "passwd" to start the change of the root password. Enter a password twice and you should see a confirmation it was changed.
6.  Type "umount /" to unmount (note there is no N in the word, this is not a spelling error) the "/" partition.
7.  Type "reboot -f" to force a reboot.
8.  Test your login to the console using the root account.