To reset your admin user's password, run the following command as the root user in a console on your Rockstor appliance:
(The "root" user is the one created during the initial install when a password was requested twice.)

/opt/rockstor/.venv/bin/pwreset

If you have forgotten the root user's password please see: Resetting root password.

If enabled, you can reset passwords with Pincards Click to reset users password with Pincards

Welcome to Pincard Manager password reset

Password reset any user with access to their current Pincard.
Note that the 'root' user (UID 0) requires an additional password sent via the email alerts system.