If you add that person’s phone number to your contacts with a specific name, their WhatsApp name will change to the one you enter in your contacts.
On an iPhone, open the Settings app and select WhatsApp. Tap the “Contacts” switch to allow WhatsApp access to your contacts. On an Android, open the Settings app, tap Apps, select WhatsApp, tap Permissions, and then give the app access to your contacts. [2] X Research source
If you have an iPhone, open the Settings app, select WhatsApp, and tap the Contacts switch to turn contacts off. Then, tap the switch again to turn them back on. Tap the New Chat icon. Tap the three dots at the top-right. Tap Refresh.
If you have an Android, you can easily delete duplicate contacts using the Google Contacts app. If you have an iPhone, go through your contact list and merge any duplicates you find. Then, adjust the names in your contacts to fix them in WhatsApp.
Using unique Apple IDs for each iPhone and unique Google accounts for each Android will resolve this problem.
