Solved! Go to Solution.
open contact in whatsapp(you want to change name for)
select 3 dot menu on top right corner.
select view contact.
again select 3 dot menu on top.
go to edit.
from there change name.
it should work.
I don't use WhatsApp, but are your contacts saved to the SIM, or to your Google Account?
I'm not sure, but if your contacts are saved locally to the SIM, it's possible that other apps, like WhatsApp don't "see" any changes you made.
Go to your contacts & click on the one you want to change & then click on storage location, you should see where it's saved to.
If it's saved to the SIM, move it to your Gmail account & sync, then see if changes made are reflected in WhatsApp?
Yeah I'm not sure where WhatsApp looks for contacts, but after you made the changes to your contact, did you Sync your contacts with WhatsApp after?