How to change procurement BU when a procurement contract is created from negotiation

Summary

How to change procurement BU when a procurement contract is created from negotiation

Content

Currently when we create procurement contract from negotiation it inherits procurement BU from negotiation. We cannot change it.

We have an entity (business unit) that provides shared services (negotiation services, things like RFx development, publishing, receive responses from supplier, evaluation, scoring and award)  to other business units. Procurement contracts are created under requesting business unit.

With currently functionality ( i believe, please confirm), we cannot change procurement BU on procurement contract when it is created from negotiation. Shared services model doesnt take effect between sourcing and procurement contracts,