Invoices can be deleted at any time; however, they are not technically deleted from the system until the next Daily Sales Register Update.
Until then, the header status changes to Deleted and the system removes all line items. This procedure enables the system to keep an audit trail of all the invoice numbers used.
To delete an invoice before the header is complete:
Press F4 to back up to the Customer field.
To delete an invoice after the header is complete.
With the document open on screen,
Choose File-->Delete Document from the menu.