Hello, userbronwinw.

I'll show a couple of ways to delink a bank account from QuickBooks Online. 

You can delink or disconnect a certain bank account by going to the Banking page. Here's how to do it: 

1. Go to the Banking page. 
2. Select the account you want to disconnect (click the blue box widget). 
3. Inside the box, click the Pencil icon.
4. Select Edit account info.
5. Check Disconnect this account on save, then click Save and Close. 

Alternatively, you can go to the Chart of Accounts page to disconnect the account: 

1. On the Chart of Accounts page, find the connected bank account you want to disconnect.
2. Click the arrow icon beside Account history, then select Edit.
3. Check the Disconnect this account on save box again, then hit Save and Close. 

Here's an article for reference in case you want more details about the disconnection process: Disconnect or delete accounts connected to online banking.

If you happen to come across any difficulties categorizing your bank transactions, you can check this article for a guide: Categorise and match online bank transactions in QuickBooks Online.

I'll keep this thread open in case you have more questions about managing your bank accounts or transactions in QuickBooks. If you have any other concerns, don't forget to add them to your reply. I'm here to help.