You can delete any cancelled bill run. This removes the bill run and associated invoices from the Zuora application. Deleting a bill run does not have any financial impact, since the cancellation of the bill run was had the financial impact of canceling the invoices.
To delete a bill run, go to Billing > Bill Runs in the left-hand navigation section to view the list of bill runs. Scroll to a bill run that you have canceled, then click Delete in the Actions column. This deletes the bill run and all of the associated invoices.