In QuickBooks Online (QBO), you can only unreconcile one transaction at a time. This is to minimize the impact of the changes, cathy105. Let's work on this together to rectify the ending balance.
Here's how to manually undo each transaction from reconciliation:
- Go to the Gear icon.
- Choose Chart of accounts.
- Find the account that has the reconciled transaction, then select View register.
- Select each transaction to expand the view.
- In the Checkmark ✔ column, select the box with the “R” until it's blank.
- Hit Save, then close the account register.

On the other hand, to restart the reconciliation, you'll have to reach out to your accountant and have them undo the entire month. Once done, we can reconcile your account again.
To learn which transactions were cleared and which were left uncleared after reconciling, you can pull up the reconciliation report.
If you need more help to reconcile your account and manage your bank transactions, I'm always here to assist you. Have a great day!