Carrier/service allocation when ShipHero doesn’t support rate shopping

We use carriers not supported by ShipHero’s native rate shopping, so we can’t automatically select the cheapest option without an external system.

We have an external system can handle the rate shopping and return the carrier + service codes for each order (but it does not generate labels).

Is there a way to update the carrier and service on an order—e.g., after packing—so that ShipHero can then print the label as usual through its native or external carrier integrations?