Changing display names on physical phone

I am trying to change the names displayed on the buttons on the phone, and on the side car.  The phone numbers are assigned to users, and even though I changed a user (unassigned/reassigned) online, the physical phone still displays the old user.  When I search the directory on the physical phone, only 4 of the 14 users appear as options.  I cannot change the names, spellings, order of names, nothing.  There are a million of these posts i've looked through without answers.  I've looked through knowledge articles, and nothing helps.  I had already called Comcast about the issue, person couldn't help me and transferred me and I couldn't wait another hour on the phone for someone else that can't help.  Please tell me how I can change the PHYSICAL phone display names (not caller ID, not outbound calls, not online, on the PHYSICAL phone - and the side panel).  Thank you