Hi @Backup Global Admin ,
Thanks for your post!
Regarding your first question, an Azure subscription can only belong to one Azure AD tenant. Any users who need to access the Azure subscription must exist in the same Azure AD tenant as the Azure subscription. You can, however, transfer the subscription to a different Azure AD tenant if needed.
Licenses are managed per-user and also cannot be shared across tenants. The documentation states,
"User accounts, identities, security groups, subscriptions, licenses, and storage cannot be shared among tenants. All tenants can have multiple environments associated with each specific tenant. Data is not shared across environments or tenants... In a multi-tenant scenario, a licensed user associated with a tenant can only access one or more environments mapped to the same tenant. To access another tenant a user needs to be invited as a guest user and may need a separate license assigned."
For your second question, the attachment you mentioned does not show up for me so I'm not sure what sort of access you are referring to. As a customer, you always you always have the ability to revoke the permissions you’ve provided to a partner. You can control the access by going to https://admin.microsoft.com > Show all > Settings > Partner relationships and removing unnecessary roles from the partner. You can also contact the partner directly and have them remove you from their Partner Center. See licensing guide.
If you have more questions about licensing, it is free to speak with the Sales/Licensing team to get support.
Global support numbers: https://support.microsoft.com/en-us/topic/global-customer-service-phone-numbers-c0389ade-5640-e588-8b0e-28de8afeb3f2
Sales support: https://www.microsoft.com/en-us/security/business/get-started/contact-us
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