Live migration of running vm and migration of templates


how is it possible to migrate a VM live from one datastore to another?
If I use onevm migrate --live i get this Response: [one.vm.migrate] A migration to a different system datastore cannot be performed live.
How can it be done using onevm on cli and how on the gui?
How is it also possible to migrate a template to another datastore?
We use Opennebula 5.4.12 with VMware vCenter 6.5.

Thank you!