How do I customize a Statement of Activity Detail report so that it EXCLUDES one of the BANK accounts in the report?

Hello there, ashlandfoodproje. 

I'll show you the easy way on how to customize your statement of activity report (Profit and Loss). 

1. Go to the Reports menu and run the Profit and Loss Detail Report. 
2. At the upper-right, click Customize. 
3. Select Filter and check the Distribution Account box. From the drop-down uncheck the account we want to exclude. 
4. Click Run report to refresh. 

You can also look into this article that will help you customize more on your report and on how to manage them: Customize reports in QuickBooks Online

If you have further questions just leave me a reply below. Take care always!