Thank you. We just did this coincidentally about an hour ago. We offlined the LUNs and removed the RDMs from the powered down VM and then performed a lun move and then reattached the LUNs to the VM and all was well. Thank you for confirming this.
Re: Removing qtree but keeping the LUN - C-mode 8.2.1
Performed the change on a live 2012 server copy data to 2 x RDM drives. Never lost connectivity to the disks but each time tested one the copy jobs that were running in parallel stopped but resumed when the other just that kept running finished. Not sure I'd like to risk this with a SQL server for example so will shut them down but it is good to know you dont need to detach / reattached the RDM to the VM. Thanks for the assistance aborzenkov...