I have taken over an account that has a CIX and a mixture of 2010 and 3020 digital phones.
I am wanting to change the extension's display names. Can this be done via programming on the phones or from network manager only.
I have read every user guide that I can find and none of them mention it.
Thank you. Sorry for the trouble on such a potentially easy question.

The DN are changed through Admin programming, which requires a password. If you Google "toshiba cix admin guide" it is easy to find it available.

The only issue with Admin programming is that Toshiba added this ability sometime in ver 2.2something. The admin ability did not exist prior to this update. It is disabled by default. At some point a Toshiba tech would have had to turn it on for an extension, usually the reception or office manager. I have turned this one for only a handful of customers who wanted to change the names on their own.

You could use system programming to enable Admin for an extension, then use that extension and set the DN names for the other phone extensions. You would need to use a 20-button phone to access PRG 204 FK34, Administrator phone.