Unpeg Intersite Orders

Community,

searched in the community,  I don’t think I have got what I need. below is the scenario

1. Belgium Site send purchase order to Canada site, so intersite order created at both sites (Belgium site purchase order, Canada site customer order).
2. Belgium site make changes, cancel purchase order lines. instead of using “Send Change Request”, Belgium site sent message using “Send Order”.

This scenario ends up in below consequences

1. Canada site approves the incoming message, result in error, customer order already exist
2. Belgium site realized the error and tried to send “Send Change Request” again,  but the message does not include changes (cancelled purchase order lines), and it does not make any changes to the customer order in Canada site. We assume the changes have been consumed by the previous message that was sent wrongly.

Question is, how we could handle this kind of scenario? either we could make Belgium site send change request include the change info or we could do unpegging and make Canada site customer order line cancelled as well(manually).

Thank you.