In my company I support contract manufacturing. So while we also have very similar processes to those mentioned above for internal design changes, I will go into the process when we have a design change at a contract manufacturer. Generally a change can be initiated internally or from the contract manufacturer (CM). When the CM initiates a change they send us a change notification as stipulated in our quality agreeement. That change is then evaluated internally to determine if design is impacted. It is also evaluated just like an internal change to determine impacts to regulatory, process, marketing, etc. If it is a design change we would work with the CM to develop a verification/validaton protocol, they would build samples and testing would be done either within my company or at the CM depending on where the capabilities lie. If everything passes we would update our specifications then send a copy of that spec to the CM and they would update theirs. In addition to gaining any regulatory approvals (world wide), we have to get lot break information from them to close out our change order and release the new revision. Our receiving inspection would be trained to start inspecting the new design.