[libvirt-users] Need help for block committing

Hi all. Can snapshots of identical images being blocked committed to the base images that are not the original ones? For example, suppose I have base0 and made a snapshot of it called SN0, then I copy base0 as base0', can SN0 be block committed into base0'? I think it's possible in theory but the block commit command just takes vm, base, and top as parameters, since the snapshot file is taken from another image I don't think I can use this command to do what I want. Or can I use qemu-img to do this? Thanks.