az disk revoke-access Revoke a resource's read access to a managed disk.
Here's why it's important to revoke access (rom Upload a VHD to Azure or copy a managed disk to another region - Azure PowerShell):
After the upload is complete, and you no longer need to write any more data to the disk, revoke the SAS. Revoking the SAS will change the state of the managed disk and allow you to attach the disk to a VM.