How do I edit and resubmit an invoice that I have already sent?

If you do not have an option to cancel the invoice, contact your customer and request that they manually reject the invoice. Once the invoice has been rejected, you can submit another.

Depending on your customer's invoicing rules, you might be able to reuse the invoice number from your rejected invoice. If they do not allow it, you'll need to choose a unique invoice number when submitting the corrected invoice.

SAP Business Network for Procurement & Supply Chain > Transaction Documents > Transaction (Invoicing)