You can create a journal entry to void an invoice in a different period, Ettahess.
However, that will not remove the link between the estimate and the invoice. Here's an article as a guide: Void A Transaction In Another Period
If you want to redo the progress invoicing, you can unreconcile your statement from August. However, I would recommend reaching out to your accountant before doing this for additional advice since it will affect your financial statement. Follow these steps on how to undo a previous month's reconciliation:
Once done, you can open the invoice and void it. Then, go back the estimate and start the progress invoicing again.
Don't hesitate to reach out to us again if you need anything else.