Well… In Horizon DaaS it is not easy to move a VDI from assignment A to B. But in the end it is possible. Let me tell you how!
first, this only possible when users have dedicated desktops. Otherwise I cannot find any good reason to do this.

  • Turn off the VDI in question
  • Make a clone from the VDI and move the origin VDI to an other “dummy” network.
  • Make sure you give the cloned VDI the correct name in vCenter.
  • Start the cloned VDI and remove the DaaS Agent
    • Remove the DaaS Agent via “Setting” > “Apps”, like any other app in Windows
    • Delete the registry key “HKLM\SOFTWARE\Wow6432node\VMware, Inc.\DaaS Agent”
    • Reboot
    • Reinstall the DaaS Agent

Now you have to wait approximately 5 minutes before the “new” VDI will apear in the DaaS admin portal. Th VDI will show up in the “Imported VMs” section.
From there you can migrate the VDI to the right assignment, like I said this is only possible with dedicated desktops. So you can only move a VDI to a dedicated desktop pool.