There is not an in-place upgrade from SSRS to the Power BI Report Server. However, migrating an existing instance of SSRS running in Native mode to Power BI Report Server can be accomplished via the following steps:

1. Back up the database, application, and configuration files of the existing SSRS instance:
   • The encryption key of the SSRS instance should also be backed up
   • The configuration files can be found within the SQL Server installation directory (<install directory>Reporting ServicesReport Server), as shown in the following screenshot:

• • The default installation directory for SSRS is C:Program FilesMicrosoft SQL ServerMRS13.MSSQLSERVER

2. Clone the Report Server Database hosting the reports for the instance of SSRS.
3. Install the Power BI Report Server instance via the PowerBIReportServer.exe file described earlier in this section; this installation can be on the same server as the existing SSRS instance.
4. Configure the Power BI Report Server instance to connect to the cloned database via the Report Server Configuration Manager application:
   • Additionally, also from the Report Server Configuration Manager, restore the backed-up encryption key
   • The reports from the existing SSRS instance will then appear in the Power BI Report Server web portal
   • The Report Server Configuration Manager is included with the installation of Power BI Report Server

The following screenshot from Report Server Configuration Manager gives the option to modify the database of the ATLASPBIRS Power BI Report Server instance:

In scenarios where the hardware or topology of a Power BI Report Server deployment needs to change, the same four-step migration process outlined here applies when migrating an instance of Power BI Report Server to a different server. The only exception is that unlike the SSRS (Native mode) to Power BI Report Server migration, new and existing instances of Power BI Report Server must be installed on separate servers. 

Migrating from SSRS instances in SharePoint-integrated mode is more complex, as it involves copying content from the SharePoint environment to the Power BI Report Server via report server command-line utilities, such as rs.exe. Of course, if the volume of reports (.RDL files) to be migrated is limited, the files could be downloaded manually. A sample script for copying SharePoint content to a report server and further documentation on this process is available at the following URL: http://bit.ly/2DoBIs9.