Our caller ID for our Avaya Partner 18D used to work. Then I programmed the phones to make it so that you could hear the dialtone whenever you pick up the phone to make a call. I also changed the names on each extension and now our caller ID does not work. What steps do I need to do to fix it? When I press feature 59, PACS R7.0 91E comes up

Right when you re-setup the extensions and changed the names that wiped out the existing data related to the extensions and the caller ID. You will need to do it all again, to do this you will need a manual to follow to program this. Whenever one alters a setting another function maybe altered too, so it always pays to check, that whenever one changes anything one MUST test each and every function again after doing so, to ensure nothing else has been affected by what has been done.
http://www.retrevo.com/support/Avaya-18D-Telephones-manual/id/2877ci760/t/2/
http://support.avaya.com/css/P8/documents/100011344

http://support.avaya.com/css/P8/documents/100065047

Above are all the relevant data you need to perform this.
It is better to follow clearly defined steps in the manuals than to re-outline it all in a post here.. so have a look in the manual and follow the steps and re-do all the Caller ID and settings again.

Please just click the link below this may help you:


http://support.avaya.com/css/P8/documents/100011344