How do global procurement managers deal with a sudden demand spike? When the demand goes down how do the global managers manage the suppliers?

CGN Generally Takes A 6 Step Approach Towards Sustainable Capacity Management:

1. Supplier Identification and Engagement - a critical first step in developing a collaborative program that defines the relevant level of intervention with suppliers
2. Deep Dive Capacity Assessments - involve “doing the homework” prior to supplier visits as well as detailed on-site assessments for identifying all capacity challenges at a business level
3. Mitigation Planning - establishes commitment through clear understanding of roles & responsibilities, timeline and investment expectations from both sides
4. Enterprise Capacity Planning & Modeling - Tactical action plans are augmented with a strategic understanding of the mid-long term supply and demand gaps across the supply base to further refine the mitigation plans
5. Governance - collaboration, coordination and control are extremely important for providing continuous focus on the common goals of the program and ensuring success
6. Action Plan Management - ultimately, relentless execution by working the plan is the key to achieving success

It is better to have Long Term Agreements and deal with the JIT system.  This will enable a lot of inventory control as well for guarantee therefore if they are global managers then they have the experience to deal with so.

By having good flxibale contracts under LTA or FWA allowing for such demand fluctuation. Also by having alternative suppliers/dealers should existing contracts fail. You may also keep a breast of market changes by keeping an updated list of suppliers.

Thanks 

I support Mr. Awad's answers and I agree with him