How do {first_name} and {name} work?
When sending, CallReply looks up the caller's number in the phone's address book. If it finds it, {first_name} becomes the first name and {name} the full name as you saved it. If not, the variable disappears cleanly: Hello {first_name}, simply becomes Hello,. So write sentences that sound natural either way, and keep the spelling right on the contact cards you use most.