If you wish to reset passwords or manage Service User Accounts manually you can do so via editing User.config found in C:\Inetpub\wwwroot\PanelDaemon_v1.5. This file is XML and looks similar to the following.
The UserPassword is a SHA1 hash. To generate SHA1 passwords, use the HashCalc to generate them:
If you wish to modify how the PanelDaemon application itself functions (for example which users can login to administer users or you change the machine Administrator's password) then consider modifying Web.config also found in C:\Inetpub\wwwroot\PanelDaemon_v1.5:
Refer to this article for more information regarding the contents of the Web.config file.