The ALTER PASSWORD statement (alter_password_statement) is required to change a user’s password.
<alter_password_statement> ::= ALTER PASSWORD
<old_password> TO <new_password>
| ALTER PASSWORD <user_name>
<new_password>
<old_password> ::= <password>
<new_password> ::= <password>
The old password must be the same as the password stored in the database catalog for the current user.
If the user name (user_name) is specified, the current user must be the database system administrator (SYSDBA).
The new password must be specified in the CONNECT statement the next time the user starts a database session.