Diagnosis
The fixed value date affects the way inwhich the billing document is posted in accounting. Consequently, youcannot change the fixed value date if the billing document has alreadybeen transferred to Accounting.
In the case of cancellation of a billing document which has not yetbeen transferred, the fixed value date cannot be changed. In this caseneither of the billing documents (canceled or cancellation) is
transferred; the fixed value date has no effect and can therfore not be
changed.
You can only change the fixed value date if the billing document hasnot yet been transferred or when errors occurred during transfer, andif the billing document is considered relevant for transfer.

System Response
The system does not change the fixed value date.