How do I reverse bank rules that were applied to old transactions?

Hi there, @sarah159.

I'll help you accomplish your task in QuickBooks Online (QBO). 

QuickBooks automatically applies your rules to transactions in the For Review tab. Then, they will show up in the Categorized tab. To reverse the rule, you can simply look for the transaction and click Undo. 

For a complete guide, follow these steps:

1. Go to the Banking menu and select Banking.
2. Click Categorized. 
3. Look for the transaction you want to uncategorize and select Undo.

They will automatically go back to the For review tab. From there, you can manually categorize it. Here's a quick guide you can use: How to review downloaded bank and credit card transactions and put them in the correct accounts.

For more info in using bank rules, check out this article: Setup bank rules to categorize online banking transactions in QBO.

Let me know if there's anything else you need by commenting below. I'm always around to help.