HI,
I found no solution to this, so I made one myself ;-)
EDIT on 2019-07-13:
##shutdown the VM
qm shutdown 106
## edit the VMID in the storage line[for me from local-zfs:vm-106-disk-0 to local-zfs:vm-104-disk-0]:
vim /etc/pve/nodes/name/qemu-server/106.conf
## rename the conf file:
mv...