How to increase size of unmanaged disk attached to classic VM

Thanks for your response Sirius.  Yes, I know the unmanaged disk scenario is in the same doc, but I think that only works for Resource Manager deployments.  Again, there's no language in the doc that mentions the Classic scenario.  Also, I've tried the Powershell listed in that section and I basically get a null array of disks.  So, I'm thinking the Classic scenario is not supported with that Powershell.

 I have also tried using the Azure classic CLI and though I can reference the disks using this command:

azure vm disk

 there doesn't appear to be a way to update the size of the disk using the update command:

azure vm disk update --help
 
help:    Update properties of a data-disk attached to a VM
help:
help:    Usage: vm disk update [options] <vm-name> <lun>
help:
help:    Options:
help:      -h, --help                 output usage information
help:      -v, --verbose              use verbose output
help:      -vv                        more verbose with debug output
help:      --json                     use json output
help:      -c, --host-caching <name>  the caching behaviour of disk [None, ReadOnly, ReadWrite]
help:      -d, --dns-name <name>      filter VMs for the specified DNS name
help:      -s, --subscription <id>    the subscription id
help:
help:    Current Mode: asm (Azure Service Management)

Any other thoughts?