To change database username password
Go to Home > Database Servers > Local MySQL Server > Databases >Database Name > Database username. Type a new password and click OK.
Type in the newDatabase user password and confirm password boxes.
Click OK.
Alternative method -
Go to Domains > Domain name > Databases (in the Applications & Services group) > Database Name > Database User Name. Type a new password and click OK.Please note changing the database username password will need the script that connects to the database password updating.
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