SO cannot be deleted for Calculated Cost

In Sales Order Product Costing when i am trying to delete my SO, system dosen't allow me to do the same (although i know that SO is a legal document and deletion is not advisable under best practices but still my requirement is like that).

In the Pricing Procedure the Actual Cost EK01 is coming after i am doing the costing.

Can anyone tell me how to tackle this scenario.

Regards,

N