Change from import data source to Power BI dataset

I have a report where I've imported data from some tables, created visuals and published it to the Power BI service. Any new reports I create can use this Power BI dataset and connect live to it, but I would also like to change my existing report to use the Power BI dataset instead of the imported dataset. Then I could have a separate pbix file for working with the import dataset and have all report files use the Power BI dataset. Is there any way to do this or do I have to re-create the report using the Power BI dataset? I don't know if it's relevant for this, but we have a Premium capacity.