Failing to Transfer Admin

Our team needs to submit a support ticket for admin transfer. Our admin is exiting the company and no longer has access to the associated email account. Although the email for the admin was changed, we cannot complete the admin transfer. We keep getting a notification that the admin is unauthorized to do the admin transfer, which we suspect is because they can no longer access the old email account. We need assistance with this transfer, and/or submitting a support ticket, please. Thanks in advance!