clear order tracking details when change date in production order - NAV Manufacturing 2009 R2

Hi Expert,

I have a question on NAV manufacturing module.

We are doing manufacturing. I create production order from following method,

Sales order → Planning worksheet → Carry out action msg.–> OK

In firm planned production order,

We can see relevant sales order from (Function → Order tracking) order tracking window. But if I change production order start date of production line order tracking details will get deleted.

Why it happen ?

Is there a way to see demand sales order after changing stat date & times in production order line ?

Please let us your valuable ideas.