Change database user passwords (plesk 10)
1. Login to plesk panel.
2. Click 'Domains' on the left side of the pane.
3. Click "Control panel" in front of the domain for which the change has to be made.
4. Select "Websites and Domains" tab.
5. Expand "Show Advanced Operations" by clicking on it.
6. Click on "Databases".
7. Select the Database for which the user password has to be changed.
8. Select the Username for which password has to be changed.
9. Enter the new password and confirm it.
10. Click 'OK' button.