Only the Account Owner (also referred to as the Primary Account Holder) with the according privileges can provide shared access for other users.
Can Magento Support Team provide shared access on behalf of customer?
Managing users and their access is the customer's responsibility, especially in the shared access perspective. Customers are encouraged to add users with shared access themselves, using the Magento Account page.
Can users with shared access transfer it to others?
Users who have been provided with shared access cannot transfer or grant such access to any other users.