Hi,
Welcome to Microsoft Q&A community forum!
Transferring an Azure subscription from one CSP partner to another is a multistep process that requires actions by the customer, the current partner, and the new partner at various stages. The following table is intended as a sequence diagram to help clarify who does what and when.
If your customer already has a CSP subscription, you can transfer their tenant to your CSP by following these steps:
https://learn.microsoft.com/en-us/partner-center/switch-azure-subscriptions-to-a-different-partner
Hope this helps
Cheers
Luca
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