How to update shipping_line for a draft order?

[test6A]

I was using DraftOrder REST Api to duplicate a draft order from an order. I'm facing an issue that the shipping_line is null and I have to update it. But it requires a handle parameter for regular shipping which I have no idea about it. I don't want to use a custom shipping. Is there anyone able to do this before? 

[lamalamaMark]

Same situation here; also looking for which handle to add to the request.

[jasonSpark]

Hello Shopify, this still seems to be an issue for the graphQL API endpoint for updating draft order.