Only Invoice with a status P can be cancelled.

Cancellation of Invoice comes in two ways.
    1. Totally cancelled invoice.
        Totally cancelled invoice will cancel the invoice and zero out the amount including the details of the particular invoice. The status of this invoice will change from P to C.
    2. Cancelled invoice and create new invoice.
       Cancel invoice and create new invoice will cancel the invoice and zero out the amount including the details of the particular invoice, status will change from P to C and create a duplicate new invoice number with a status D. This newly created invoice will then can be edited. The system will create an auto increment invoice number for the newly created invoice.