Changing the Password of a Database
User 
You can use the Database Manager GUI to change the password of a database user.
Prerequisites
The database instance is in the ONLINE operational state.
Procedure
...
1. Choose Instance ® Configuration ® Database User...
2. Enter the name and password of the database administrator that is the owner of the database user whose password you want to change.
3. Select the desired database user.
4. Choose Properties.
5. Select the tab page General and then choose Password Change.
6. Enter the old and new passwords and save your entries.
Note the 
Conventions for
User Names and Passwords.
Result
The password of the database was changed.
See also: