In order to redirect a report wich was deployed into Power BI Online from QA to PROD environment, Is it really necessary to do that modification in a new PIB desktop file? Isn't it possible to do that from the service itself?
As far as I know, there is no any option on the service to change data source for reports currently. I would suggest you submit this as an idea on Power BI Idea to improve Power BI on this feature.
Engage and empower students with Power BI!
Continue your learning in our online communities.