1. From the home screen, tap Messaging.
   
2. Touch and hold the desired message thread.
   
3. Tap Add to block list.
   
4. Tap OK.
   
5. To unblock a contact, tap the Menu icon.
   
6. Tap Blocked messages.
   
7. Tap the Blocked list icon.
   
8. Tap the desired blocked number or contact.
   
9. Tap Remove from block list.
   
10. Tap OK.