Hi, I'm Ashik. Welcome to JustAnswer. I'm reviewing your question now, and will post back with your reply ASAP
You copy the contacts using SIM card. On the Z431, open Contacts. Click Options, select Settings, select SIM Management. Select Copy Contacts to SIM card. Select all contacts and click Done (left soft key)
Then put that SIM card on your Z432, open Contacts. Click options, select Settings, select SIM Management and select Copy Contacts from SIM Card. That will do it.
If you have any questions or having any difficulty transferring the contacts, please let me know and I will continue to help you