Here's a quick and easy way to change the Service Console VLAN ID on an ESX host:

1) Log in to the host console as root, or SA to root
2) Check which vSwitch the Service Console is on with the command "esxcfg-vswitch -l"
3) To set a vlan id on the service console: esxcfg-vswitch vSwitch0 -v X -p “Service Console” (replace the "X" with the VLAN ID)
4) To remove the vlan id completely, just set it to 0, like this: esxcfg-vswitch vSwitch0 -v 0 -p “Service Console”

That's it! The change takes place immediately. No reboot is required.