Unregister VMs from vCloud Director?

Hi

We have a few VMs which we have imported into vCloud Director and now we want to remove them from vCloud Director. Unregister them but not delete them because we want to move them to a different location. Does anyone know an easy way to do this? There doesnt seem to be an easily supported method. Unfortunately Cloning the VMs (as a way to remove them from vCloud Director) is not a simple operation since 1 VM is 4TBs is size. I am looking to just unregister the current VMs. Anyone have any bright ideas?

Thanks

Joel