dear expert，
we got a issue, we can't change assignment through VF02. but some billing in other system can be changed of this field. why it that, i didn't found any one use SHD0 to control.
hi Aravind B,
we need to modify it manually, in some system, this field is allow change, but some others is not allow change. it looks so strange.
attached the comparation shortcut.
I can't remember seeing this field as modifiable in a standard system. Have you tried to look for project documentation? If this is the result of a custom enhancement, most probably, it is documented and uploaded somewhere. If there is no documentation available, you can try checking the logic in MV60AF0F_FELDAUSWAHL_SONDERREG in the system, where this field is modifiable.
I am also not sure how well this process will work as a regular practice via VF02, considering that you already have a FI document created.