Hello Gyana,
- In VTFL, at Header level you may make standard settings as per the requirements and at Item level check the pricing type which should be "D" and rest could be done as standard as you wish to have.
- Please go to VOV8 > Enter the Re Order type > enter Billing type at Dlv-rel.billing type.
Please test this first in sandbox.
I tested the same in my sandbox and able to successfully create Credit Invoice with reference to RE Delivery document.
Regards
Kamlesh