System does not change the DFF value through FBDI

Summary:

Dears Team,

I am facing an issue while I am changing the DFF value at the header level through FBDI, when I try to do this, 1st system asks me to provide the line and schedule information which I do not require to change, but I provided it as it is test instance, system successfully created new line. But my main purpose does not achieve that the system does not change the DFF value.

Can anyone suggest it is possible to update the DFF from FBDI or I am missing something in the steps.

Thanks.