When you forget your account password, you can easily reset it using a root account. But when you forget your root account password, then you're in a bad situation. You can't reset your root account password using a regular user account, as a user account can't perform such tasks in general parafrase tool.
In some situations, you may need to access an account for which you've lost or forgotten a password.
Step 1: Boot into recovery mode. Restart your system. ...
Step 2: Drop Out to Root Shell. ...
Step 3: Remount the File System with Write-Permissions. ...
Step 4: Change the Password.