Allied Telesis AT-S63 - Manual (Page 740)

Chapter 32: PKI Certificates and SSL
740 Section VII: Management Security
Enter certificate name (ALL - delete all) ->
6. Enter the name of the certificate you want to delete. (This field is case
sensitive.) To delete all the certificates, enter ALL.
7. After making changes, type R until you return to the Main Menu. Then
type S to select Save Configuration Changes.