how change ns for many user?

[nimafire]

hi.
in reseller level.
for example my dns are:
ns1....
ns2....

and my users dns so are ns1 and 2.
if i want to change my ns to for other ns.how i can change my old user's ns at once?instead of i change it user by user?

[smtalk]

http://help.directadmin.com/item.php?id=141