Adding custom discount in an order

[rishikesharya]

Hi,

I have to duplicate an order through REST API and create an order of 0 value. For that, I need to add a custom discount of 100%  in that new order. 

How can I do that?

[ErSanjay]

@rishikesharya  can you please add more details 

[rishikesharya]

I have to create an order with a 100% discount on the total. I don't want to create a coupon code for the discount because of the code leak issue. I have to create the order through REST API and add a custom discount of 100% just like we do while creating an order from the draft.