A problem with answering this question is first that the main SYSTEM keeps this info not the handset, so for the 3x8, 6x16, and 8x24 systems you can do the following (PROVIDED, the installer did not change the passwords to access).
Press FEATURE * * 2 6 6 3 4 4
Enter Password: 2 6 6 3 4 4 Display will read: " A. Configuration"
Press: NEXT Display will read: "B. General Admin"
(NEXT is always the button on the right of your lines/extension list, 2nd button down from top.)
4. Press: SHOW Display will read: "1. Sys speed dial" (SHOW is one key up from NEXT)
5. Press: NEXT Display will read: "2. Names"
6. Press the SHOW Display will read: "Set names"
7. Press: SHOW Display will read: "Show set:__"
8. Enter the extension number of which you wish to change the name Display will read: "<##:name>"
9. Press the CHANGE softkey
10. Using the dial pad spell out the name Ex: If you need the letter K press the 5 key twice and then press # to confirm the letter. Continue until the entire first name is spelled. (note: you are limited to 7 characters)
11. Press: NEXT (if you fail to do this step, the name will not be saved!!!)
12. Press the RLS key
I may be mistaken however I think you have to be on a model M7310, T7316, or M7324 phone (there should be at least one usually at the main desk) in order to program I don't think you can directly do it from the T7208.
Hope this helps.
on Feb 01, 2019