User attribute switching (ldap)

Hi All,

I'm trying to switch my ldap user attribute in Moodle 2.4 from "samaccountname" to "mail". My district wants to do this because we're getting an SSO portal. However, when I try to log in it creates another account. My original account (using samaccountname) and another account with my email (using mail). I just want it to authenticate using the mail attribute on the original account created using "samaccountname". Is there an easy way to do this? I have 5k+ accounts to change over. 0_o

Thanks,

Tyler