I've just converted to On Line. How to I run financial reports, BS & P&L for prior period?

I'm happy to see you here in the Community, @-mqrparish-org.

I'd like to make sure we're on the same page so I can give you the right amount of information. To start with, can I ask what platform or service are you using prior to converting to QuickBooks Online? Any further details about this matter would be a great help for me to narrow down this concern.

On the other hand, if you've utilized QuickBooks Desktop before, you can run and customize the date of the Profit & Loss report as well as the Balance Sheet depending on your desired period in QuickBooks Online.

To do that: 

1. Click on Reports at the left pane.
2. Look for Profit & Loss or Balance Sheet at the search box. 
3. From the Report period section, enter your desired date.
4. Select on Run report. 

You can also check out the short video clip found in this link that provides more tips about sorting and customizing reports in QuickBooks Online: How to Customize Reports: Basics, Sorting & Date Ranges.

Please get back to me if you're referring to something else or if you have further questions. I'll make sure you're all set. Have a good one!