How to find out the password from wifi, knowing the old one?

Question

Network administration

At work, all employees used Wi-Fi for free, but they figured it out and want to change the password (I don’t know why they haven’t changed it yet), but so far Wi-Fi is under the old password.
How can I find out the new password when it is set?
PS Please do not write answers like: "Ask someone who knows", "Just like the old one found out", etc.))

Answer 1

the old password does not help, if the router is old wep encryption, then you can hack otherwise wpa2/psk only by brute force

Answer 2

habrahabr.ru/company/xakep/blog/143834
habrahabr.ru/post/151688
or if the router is within physical reach, then just roll it back to the initial settings =)