If you are interested how to change MySQL password in the ISPmanager, do the following steps:
Choose the point “Databases” in tab “Tools” – you will see all your databases. Then select the database, that should have its password changed and click the button “Users” in the right upper corner. After that select the user that should have his password changed and click the button “Change” in the right upper corner. Then input the password in the fields “Password” and “Confirmation”.