Hi Norbert,
I asked around and the SQL Expression should use the same log on info as provide by the Data Source connection info so it should not require a separate connection. Same for a Command Object.
So as long as you are updating the Connection property bag with the new log on info, which does require a Schema and User name, unless you created the Report to use Trusted Authentication, that new log on info should work.
So nothing else to suggest since no code snippet provided....
Thanks again
Don
