At the moment, the Undo Bank Reconciliation in Quickbooks Online feature is not available in any plans. It is only available in Accountant.
To UNDO IT, first sign in to your QBOA account.
Navigate to the Client home page screen.
Click on the company logo (upper right corner)
Under Tools, select Reconcile.
Choose a bank account for UNDO reconciliation.
Hover your mouse cursor over the reconciliation month you want to undo (under Ending Balance, Auto Adjustment, or any column), and you will see a UNDO button to the right next to the Auto Adjustment column.
Click the UNDO button.
A new Undo Reconciliation screen will be displayed.
Click the OK button.
The Success screen will then appear.
Click OK once more.
It will no longer appear on the list of Reconciliation History & Reports.