Reverse Delivery Note Copy from Reserve Invoice

SAP 2007B PL14

SQL SERVER 2008

I would like to consult how to reverse Delivery Note which was copied from AR Reserve Invoice.

The operation flow is as follows:

1. SO

2. SO Copy to AR Reserve Invoice

3. Incoming Payment

4. Copy 'Paid' AR Revserve Invoice to Delivery Note

We have tried to cancel the incoming payment in order to re-open the Delivery Note but it failed.

How to cancel the Closed Delivery Note?

Thanks in advance,

Vivian Chan