[Stakeholders] What do you do when a stakeholder keeps changing requirements after suppliers have already been engaged?

I would slow the process down enough to make the cost of the changes visible. Requirement changes after supplier engagement do not just create inconvenience. They can distort pricing, weaken supplier confidence, and create avoidable rework on both sides. So I want the stakeholder to see that consequence clearly.

Then I would decide whether the changes are still within the original scope or whether...