root@PROXMOX01:~# pveversion -v
pve-manager: 2.3-13 (pve-manager/2.3/7946f1f1)
running kernel: 2.6.32-19-pve
proxmox-ve-2.6.32: 2.3-93
pve-kernel-2.6.32-16-pve: 2.6.32-82
pve-kernel-2.6.32-19-pve: 2.6.32-93
lvm2: 2.02.95-1pve2
clvm: 2.02.95-1pve2
corosync-pve: 1.4.4-4
openais-pve: 1.1.4-2
libqb: 0.10.1-2
redhat-cluster-pve: 3.1.93-2
resource-agents-pve: 3.9.2-3
fence-agents-pve: 3.1.9-1
pve-cluster: 1.0-36
qemu-server: 2.3-18
pve-firmware: 1.0-21
libpve-common-perl: 1.0-49
libpve-access-control: 1.0-26
libpve-storage-perl: 2.3-6
vncterm: 1.0-3
vzctl: 4.0-1pve2
vzprocps: 2.0.11-2
vzquota: 3.1-1
pve-qemu-kvm: 1.4-8
ksm-control-daemon: 1.1-1
root@PROXMOX01:~#

Change VMID from 902 to 202

1. Stop/Shutdown a VM.
2. Login using SSH to Proxmox Machine or using Shell menu in Web Interface.
3. Rename image directory name and image filename.

   root@PROXMOX01:/# cd /var/lib/vz/images/
   root@PROXMOX01:/var/lib/vz/images# ls
   101  102  201  902
   root@PROXMOX01:/var/lib/vz/images# mv 902 202
   root@PROXMOX01:/var/lib/vz/images# cd 202
   root@PROXMOX01:/var/lib/vz/images/202# ls
   vm-902-disk-1.qcow2
   root@PROXMOX01:/var/lib/vz/images/202# mv vm-902-disk-1.qcow2 vm-202-disk-1.qcow2
   root@PROXMOX01:/var/lib/vz/images/202# ls
   vm-202-disk-1.qcow2

4. Rename configuration filename

   root@PROXMOX01:/etc/pve/nodes/PROXMOX01# cd /etc/pve/nodes/PROXMOX01/qemu-server/
   root@PROXMOX01:/etc/pve/nodes/PROXMOX01/qemu-server# ls
   101.conf  102.conf  201.conf  902.conf
   root@PROXMOX01:/etc/pve/nodes/PROXMOX01/qemu-server# mv 902.conf 202.conf
   root@PROXMOX01:/etc/pve/nodes/PROXMOX01/qemu-server#

5. Edit configuration filename

   root@PROXMOX01:/etc/pve/nodes/PROXMOX01/qemu-server# vi 202.conf

   202.conf :

   boot: cdn
   bootdisk: ide0
   cores: 1
   ide0: local:902/vm-902-disk-1.qcow2,size=10G
   ide2: local:iso/CentOS-6.4-x86_64-minimal.iso,media=cdrom,size=350546K
   memory: 1024
   name: FMIVDLWEB02
   net0: e1000=CA:16:F5:91:8E:AF,bridge=vmbr0
   net1: e1000=26:75:3B:B8:31:01,bridge=vmbr1
   ostype: l26
   sockets: 1

   change line 4 with :

   ide0: local:202/vm-202-disk-1.qcow2,size=10G

6. Result