Allied Telesis AT-S63 - Manual (Page 351)

AT-S63 Management Software Web Browser Interface User’s Guide
Secton V: Virtual LANs 351
Note
Untagged ports that are added to a VLAN are automatically removed
from their current untagged VLAN assignment. Untagged ports that
are removed from a VLAN are returned to the Default_VLAN.
Removing an untagged port from the Default_VLAN without
assigning it to another VLAN leaves the port as an untagged
member of no VLAN.
The modified VLAN is now ready for network operations.
8. From the Configuration menu, select the Save Config option to
permanently save your changes. (This option is not displayed if there
are no changes to save.)