I know a way how to quickly delete all your bank transactions in QuickBooks, @ktcarnahanlawn.

You can tick the Date box then use the Exclude option in QuickBooks Online to delete all your downloaded bank transactions.

Here’s how:

1. Select the Banking or Transactions menu, then go to Banking.
2. Click the bank account.
3. In the For review tab, tick the Date box and press Exclude.
   

If you've already categorized the transactions in the program, you can go to the Categorized tab to delete them. You can check this reference to learn more about removing transactions: Exclude a bank transaction you downloaded into QuickBooks Online.

Once done, you can use this information to disconnect the account from online banking. Then visit this reference to add your new account to QuickBooks: Connect bank and credit card accounts to QuickBooks Online.

Leave me a message below if you have any other banking questions or concerns. I’m always here to help. Take care!