Hello @Olivier Hardy Thank you for reaching out to us on Microsoft Q&A platform. Happy to help!
I understand your requirement about moving resources from BizSpark Subscription (disabled) to a new Pay-as-you-go Subscription. Since the BizSpark Subscription is disabled, moving resources to new subscription is not possible without the help of subscription management team. For this specific issue, I recommend you raise a support request from your Pay-As-You-Go subscription. The ticket enables you to work closely with the support engineers and get a quick resolution to your issue.
Here is the link - https://docs.microsoft.com/en-us/azure/azure-portal/supportability/how-to-create-azure-support-request to create support case.
FYI: Azure Billing and Subscription Management support is included in the Basic Support Plan without any charge.
https://azure.microsoft.com/en-us/support/plans/
Let us know if you need any further assistance!
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