passwd can change passwords. dscl can also change a password for an account (in this case the xadmin account) using the passwd extension:
dscl . -passwd /Users/xadmin
https://www.macissues.com/2014/05/31/how-to-change-or-reset-your-password-in-os-x/
http://community.centrify.com/t5/Community-Tech-Blog/How-to-create-a-Hidden-Local-Admin-account-on-Mac-systems-Redux/ba-p/14649#
