Is there any reporting to show what is causing a Review Period to be in use?

Summary: We recently discovered that one of our review periods had the incorrect date and overlapped with our newest review period. We had planned to alter the dates of our new period but can not due to it being in use. We have deleted all objective plans and the users inside of it, as well as removed the document period from a talent template, but it still says it is in use preventing us from editing it. Is there any OTBI reporting that shows what is connected to a specific review period?