To remove the setting, please perform the following:
1. Open Microsoft SQL Server Managment Studio
2. Start a new query, and in it run the following script :
DECLARE @RC int
DECLARE @ContextName nvarchar(512)
set @ContextName = 'SSRS'
EXECUTE @RC = [dbo].[DeleteSettingsContextByName]
3. Check that Knowledge Portal settings dialog in the Configuration Manager shows empty fields.
NOTE: The above SQL was run base on the Enterprise Reporter database name dbReporter. If different name was chosen during the setup, please change the dbReporter to the respective name. Please perform a backup of the database before running the above query.