AD:

    General tab:

       -Firstname/Lastname (Whichever is relevant)

       -Display Name

       -E-mail

   Account tab:

       -User logon name

       -User logon name (pre-Windows 2000)

   Attribute editor (for primary email address)

        -Open the user object via a group that they are a member of (not by searching for them)

        -Find and open 'proxyAddresses'

        -Add the new email address, prefixed with 'SMTP:' in capitals

        -Delete the previous primary address and re-add it, prefixed with 'smtp:' in lowercase


^This is a user that changed their last name from 'Taylor' to 'Hagan'


Following these steps will eventually sync to office.

AD:

    -Change account name.

    -Change managed apple ID to new email address.

    -Change email address to new email address.

This will transfer all iCloud data to be under the new email email address.