On this page you can find information on how to reset Skype for Business PINs for both person and role-based accounts.
Skype for Business uses a PIN for authenticating yourself when dialing in to a conference and logging in an IP phone without a computer connection. Below are the instructions on how to change it.
If you are not able to log in to a role-based account or don't know the password for that account, please contact your local IT Pro. They can manage the password for these role-based accounts.