The Reporting Services Configuration Manager is used to configure your Reporting Services installation if it is set to ‘Native Mode'.
This configuration is necessary to get your reporting environment up-and-running. The Configuration Manager is used to configure the Report Server service account, create and configure the report server database, create and configure the Report Manager and Report Server URL's, configure server mail settings, etc.
If Reporting Services is installed in ‘Integrated Mode' it needs to be configured in Microsoft SharePoint.