You can reassign ownership, but the drive needs to be a spare.
Here's a run down of the commands to move ownership of a disk and disk partitions.
for removing disks with root partitions be sure to include the -data true tag and be in advanced mode.
storage disk option modify -node * -autoassign off
disk removeowner -disk x.x.x -data true
disk assign -disk x.x.x -data true -owner NODEx
disk show -fields data-owner, root-owner
storage disk option modify -node * -autoassign on