[from qcow2 to vmdk]
qemu-img convert -f qcow2 -O vmdk whatever.qcow2 whatever.vmdk
[from qcow2 to raw]
qemu-img convert -f qcow2 kvm_source.img -O raw kvm_destination.img
qemu-img convert -f qcow2 -O vmdk whatever.qcow2 whatever.vmdk
[from qcow2 to raw]
qemu-img convert -f qcow2 kvm_source.img -O raw kvm_destination.img