Search for a contact based on various search criteria like name or phone number. This will search for ALL your contacts across all lists, not just the 50 that are displayed in the SMS chat page.
Navigate to SMS Chat.
The SMS Chat page will be displayed.
Enter the exact name or phone number of the contact you want to search in the first field.
The search results based on the given name or phone number will be displayed as you type in the search box.