@Adalid Bori Thanks for responding with details. You may want to check if your MSP has CSP legacy subscription or on a Modern platform.
If it is a CSP legacy, then transfer is possible to Enterprise Agreement subscription.
If it is on a modern platform, then transfer is not possible. You need to perform resource migration.
Reference document link - https://learn.microsoft.com/en-us/azure/cost-management-billing/manage/transfer-subscriptions-subscribers-csp#transfer-csp-subscription-to-other-offers
Hope this clarifies!
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