There isn’t an option to delete a reconciliation report. If you're trying to undo a reconciliation, follow the steps below:
Go to Accounting tab and select Charts of Accounts.
Locate the account, and click View Register from the ACTION column.
Identify the transaction to edit.
In the reconcile status column, repeatedly select the top line of the transaction to change the status. C - Cleared R - Reconciled Blank - Not cleared or reconciled
Doing this will remove the transaction from its reconciliation report.