[grace-baker Hexnode 10 February 2020 grace-baker Moderator]

Hey, Thanks for reaching out to us.

You should disenroll the devices before they are re-enrolled.
To disenroll, please navigate to the Manage tab, select the desired devices and choose the ‘Disenroll Device’ option from the Actions drop-down.
If the device is still listed in the Manage tab, click on the Actions button and choose ‘Mark as disenrolled’ option. The device will now be removed from the list.

Hope this was helpful!

Cheers!
Grace Baker
Hexnode MDM