Are you talking about moving VMs or vAPPs?
vCD is a bit inconsistent when it comes to VMs and vAPPs. Depending on which UI and which entry point you use, some functions are not avaiable.
In vCD 9.7 HTML5 UI you can only move / copy on VM from one vAPP to an other vAPP in the same OrgVDC.
But you can move/copy a complete vAPP to a different OrgVDC:
vApp: Action -> Move (Copy) to...
If you want to move a single VM which has no vAPP around (every VM has it's VAPP, even if its not shown in HTML5 gui) you can archive this in the old flex client.
Here the VMs without vAPP is listed in the vAPP menu even if it does not have a vApp container around