How do you change a port's VLAN (Virtual Local Area Network) membership and how do you delete a VLAN?

To change membership, either re-enter switchport access vlan <new-id> or use no switchport access vlan to return to VLAN 1. To delete a VLAN, use no vlan <id> from global config.

Changing VLAN membership:

• Reassign to a new VLAN: switchport access vlan 30 — overwrites the current assignment
• Return to VLAN 1: no switchport access vlan — removes the VLAN assignment, port reverts to default VLAN 1

Deleting a VLAN:

Switch(config)# no vlan 20

Critical warning: Before deleting a VLAN, reassign all member ports to a different VLAN. If you delete VLAN 20 while ports are still assigned to it, those ports become orphaned — they can't communicate with anything until reassigned.

Deleting ALL VLANs:

• Use delete flash:vlan.dat or delete vlan.dat
• You must reload the switch afterward
• This is essentially a factory reset of VLAN configuration

Full factory reset procedure: Unplug all data cables → erase startup-config → delete vlan.dat → reload