Hi and welcome to the forums. I’m the Product Manager for Queryable Encryption at MongoDB. Changing KMS providers in the way you envision is not something we support today. There may be ways to hack this, but this is a case where you may want to use the per-document keys feature of CSFLE, depending on your query needs. Let me send you a PM on the side to learn more about your use case as it is something I’ve envisioned supporting.