How do I get reports distributed by an employee that is no longer with company

Hi All

I started with a company that had some reports/dashboards shared by the previous person in my position.  I have people requesting access to these reports but I can't see the requests because I don't own the dashboards.  

How can I transfer ownership of all reports that are out there under this person? 

I don't have the original pbix file

Thanks

Cathryn