Remeber, prior to these steps you must find the desired User in the Users module.
Change Username
To change a TradeSchool Account username, you must uncheck and re-check the Allow TradeSchool Access box under the Security > Access tab.
This will re-prompt you to put in a new Username and reset the password as well.
Reset Password
To reset the password, click the Reset Password button under the Security > Access tab.
It will let you put in a temporary password for the User you're on.
Upon the person's next login with the temporary password, they will be prompted to setup their new password.