Samsung 08/2004 - Manual (Page 174)

Access codes
173
You cannot change the PUK2. If you lose the code,
contact your service provider.
Call barring password
The 4-digit call barring password is required when
you use the Call Barring function. You obtain the
password from your service provider when you
subscribe to this function.
You can change this password using the Change
barring password menu option. For further
details, see page 82.