Not sure if you talking about the hostname (ID on the switch) or a VLAN ID, as in the title.
But you can give a hostname and also give a name to a vlan ID.
Go Switching > Switches and then select the switch. Ones on the Switch on the top left side you can adapt the Hostname of the switch.
You can disable not used port manually. The port will be down anyway if nothing is pluged...but i guess you would like to make sure that nobody can connect.
hope this helps
Roger