Change Facebook group privacy from secret to close?

[Mehran]

I have a group with more than 2800 members, and one of the admins misguidedly change the privacy settings to secret which means potential members now can't find us, let alone make a request to join. Facebook doesn't let groups with 250 or more to lessen their security settings.
Can anyone help me in changing this privacy of the group.Please help me in this case

[abraXus]

you have too many members - there is no way to change it once you have that many members