Updating the passwords for FTP Accounts in version 3 of the Helm Control Panel is easily accomplished.
Log into your HELM control panel.
Click on the Domains icon.
Click on the Domain for which you would like to update the FTP Account password.
Click on the FTP Accounts icon.
Click on the FTP Account in the list for which you would like to change the password.
Enter in the new password you would like for the FTP Account and click Save.
You have now updated the password for your FTP Account.