Update Request data at Order header level and line level

Hi All,

I wanted to update the request_date for an order at the header and line level using oe_order_pub. Does anybody have any code for doing achieving this? If yes can you please give?I had the doubt before passing the order record do I have to populate each and every field or just the request date for the record and if i don't populate will those field be updated to null? 

Really appreciate your help on this.

Thanks and regards,

Samrat