WARNING!!! Reassigning disks that have data on them can cause data loss. Make sure you're not reassigning the wrong disks.
Essentially you can use the disk command to reassign disk ownership. This might require you to run the priv set advanced command to get access to this command. Below are a few syntaxes you can use.
disk show -v this command shows all disks on both controller heads and the current owner
disk show -n this command would show all unassigned disks (wouldn't apply to you at this time)
disk assign -s unowned DISK_NAME you'd need to run this command from the command line of the filer you'd like to remove ownership from first.
To put it simply you can first go to the command line of the filer that has the disks you'd want to remove. Run the sysconfig -r command to show all disks for the system you're on. Identify the disk name; examples would be like 0a.71 or 0b.14.3
Then run the disk assign -s unowned 0b.14.3 command for the disk you've identified. Confirm the disk has been unowned by running the disk show -n command which should then show the disk as a spare.
Once that's done; login to the filer you'd like to assign the disk to and run the disk assign DISK_NAME for the disk you'd like to assign. Example: disk assign 0b.14.3
You can then verify if the disk has been assigned to the filer you're logged into by running the sysconfig -r command (it should show up in the spare section)
Details can be found in the Technical Report below