I appreciate you posting here in the Community, Janice. I can help you disconnect your bank account from QuickBooks Online(QBO).
Before disconnecting your bank account, please ensure all pending transactions on the banking page are added and matched. It is important to note that disconnecting the automatic banking updates will delete any transactions in the For Review tab.
Once done, let's go ahead and unlink the account. You can follow the steps below:
Go to Transactions, then Bank transactions.
Select the tile for the bank account you want to disconnect.