There are a couple of ways to cancel a processing invoice. You can just delete the invoice while it is still in the "Processing" state. In order to delete the invoice just click the box to the left of the invoice number. Scroll down to the bottom of the page and change the dropdown box to "Delete". Then hit the "go" button. The other option is to email us the invoice number and we can delete it for you. If you just want to edit the invoice and resend it, then emaill us the invoice number and we'll change the status back to "In Progress". This way you'll be able to make changes to the invoice and send it again. Please let us know if you have any questions. Thanks for using BillMyClients.com!