https://docs.virtuozzo.com/virtuozzo_7_command_line_referenc e/managing-virtual-machines/prlctlvm.html#managing-virtual-d evices

prlctl set <VM_name> {--device-add hdd | --device-set hdd<N>}
[--image <file>] [--size <size>] [--iface <ide|scsi|virtio>]
[--subtype <virtio-scsi|hyperv>] [--position <pos>]
[--enable|--disable]

--device-set hdd<N> Modifies the parameters of an existing virtual hard disk.
Virtual hard disks are named using the hdd<N> format where <N> is the drive index number starting from 0 (e.g., hdd0, hdd1). To obtain the list of disk names, use the prlctl list command with the --info option.

--image <file>
Specifies an image file that will be used to emulate the virtual disk.

If the specified image does not exist, it is created and used to emulate the virtual hard disk.
If the specified image exists, it is used to emulate the virtual hard disk.

prlctl set VMNAME --device-add hdd --image /home/hdd/VMNAME(.hdd)
Creating hdd1 (+) scsi:1 image='/home/hdd/VMNAME.hdd' subtype=virtio-scsi

VM configuration validation result(s) :
* The image file "/home/hdd/VMNAME" used by hard disk 2 does not exist.Hard disk 2 will not be connected at the virtual machine startup.
Failed to configure the virtual machine.

prlctl set VMNAME --device-add hdd
mv /vz/vmprivate/ID/harddisk1.hdd /home/hdd/
prlctl set VMNAME --device-set hdd1 --image /home/hdd/harddisk1.hdd