if you want to include an intent based api:

POST /DeliverOrder/{OrderId}

This is not a very good route. DeliveryOrder is not a resource. Even if it was OrderId is not the indentifier for a DeliverOrder resource. The semantics are all wrong.

If the Id is in the route, it should navigate to a resource. If it is a parameter on how to execute a command, then it should be a query string parameter. The route should either look like this:

POST Order/{OrderId}/Deliver

or

POST /DeliverOrder?orderId={OrderId}