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.
If you have the Invoice Settlement feature enabled, when you remove a bill run, all the bill run associated credit memos are also removed.
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.