reverse Ship confirmation load

We ship mostly configured items and relieves inventory at ship confirm.

We used pooled shipment to deliver the hub.

For many reasons, the hub needs to return one or all the shipment of the load.

How can we reverse shipment confirmation? Is there a workaround?

Exemple:

1/Create 2 sales order => shipment n°10 et n°20

2/Create a load with an intermediate address (hub) including this two shipments

3/Approve load

4/ Confirm load.

How can we return the shipment n°10? How can we attach a new load number to this shipment?