Error Message V1810 - Make to Order No Change delivery plant in Sales Order

Hello, for a client where I'm setting the flow intercompany , but i have an error on the Sales Order when I must be change delivery plant.

Scenario: Make to Order, Product configuration, Sales Order BOM created by CS60

Step:

1 - I create sales order fo company X delivery plant 1000

2 - Creates Order BOM on plant 2000 Company Y

3 - creates MRP Planned Order

4 - Convert Planned Order to Production Order

For different issues can happen that you decide to ship the goods to a different plant than the X. Production Plant remains 2000.

If I try to change the plant on the Order system stops me with the following error:

Message V1810 - Plant can no longer be changed

Diagnosis

The plant can no longer be changed in the Following situations:

The item has been assigned to a project.

There is a production order for the order item but it is not a staticassembly order.

Already have accrued costs.

For the very complex structure of the product I can not delete the production order and sales order BOM.

How do I handle these cases?

Can anyone help me?

Best regards

Giuseppe