Note: Undoing a reconciliation in QuickBooks Online should be done with caution, as it may affect your financial statements and reports. It is recommended to consult with a bookkeeper or accountant before undoing a reconciliation if you are uncertain about the impact it may have on your financial records.

Log in to your QuickBooks Online account.

On the left-hand sidebar, click "Bookkeeping."

At the bottom of the new sidebar, click "Reconcile."

This will bring you to the reconciliation page. Select the account you want to delete the reconciliation for. The, on the top right, click "History by account."