Change in delivery date on Parent order

Hi,
I have 1 level of item. Lower level item have BOM and Route attached to them and they have been setup as pegged supply on its parent BOM. When we run MRP, the system calculates Order and delivery date for both the parent and child item. when we change the delivery date of Parent item, for the child item in the job i can see the same order and delivery date.

In the Master planning module → Common → Planned orders → select any order and change the delivery date, In the Planned order details → Route (Check order and delivery date for the Parent and child item)

can anybody explain me on this

When you change the date you will be asked to reschedule, and you will be asked to reschedule reference orders (your child orders in this case). If you are changing it on the sales order then the planned orders should reschedule through. However in your periodic in production check you have schedule references checked in the default values.