To Undo Bank Reconciliation in Quickbooks Online, follow the steps below.
The first step is to select Banking from the left menu.
After that, go to the top of the page and pick Banking. Finally, go to the top of the page and select Account.
Select Go to Register/Account History from the Action column above.
Now, one by one, look for the transaction that needs to be reconciled.
Then, on the transaction tab, highlight it.
Then, on the top line of the transaction, between the Amount and Deposit or charge and payment amount, hit the R.
By clicking in this field, you can alter the transaction's status from Blank=unreconciled to C=Cleared.
Now press the Save button.
A pop-up window will appear, similar to the one seen below, prompting you to select Yes.