Existing Power BI Reports and Data sources (SharePoint & Accounting Systems) to OTBI

Hello, just trying my luck to raise my questions here - maybe you encountered similar scenario or can relate to this.

Our team have existing Power BI Reports already and most of the data sources or repository is in SharePoint and different accounting systems. Now, instead of these data sources systems mentioned (SharePoint & Accounting systems) to be used in reports, we will now migrate in Oracle Transactional Business Intelligence (OTBI). What are the best ways to keep these data sources in existing Power BI Reports when we will now use OTBI as our data source moving forward. what we would what to happen is that, all the upcoming data from OTBI must be captured in existing Power BI reports so that we can now let go those mentioned data sources (SharePoint & Accounting systems)