Is there any way that the Domino Admin can change the password of any user existing in the Domino User Directory from console.
Also what is the attribute name of the field storing the user passwords.
Subject: No
New to Domino, eh? 
If you mean can one change the Notes password of a user, then the answer is uneqivocably No, no, no, absolutely not.
If you mean can one change the internet password, then certainly – but not with a console command. Since it’s a field in the person document, you would edit that field.
If by “attribute name” you mean the field name of the internet password field in the person document, it’s “httppassword”.
If instead you want to know how the pasword is stored in the ID file, it’s not; it’s used as the encryption key for the sensitive contents of the file (like the Private Key), and is notactually stored as an entry itself.