I have solved this issue. I will describe my method for doing this transfer.
First thing, you can disable writing to the Samba share with the option “Samba write access”. By un-ticking this option, it essentially disables the drive.
Next I removed all GPOs pertaining to Drive Mapping. I then created a GPO to delete the P: and M: drives (the old drives that were pointing to ucs-master). I can then push that group policy update, and restart all devices. After I’ve verified that all the mapped drives were deleted, I can then re-enable the GPOs that map the new drives. Once again, push the group policy update and restart the clients.
This method missed any stragglers that were off or sleeping when I made the change. But disabling write access meant that those clients were much easier to identify.
I don’t think this was the best solution. But it -a- solution, I suppose…