You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Can you please help me to change my existing reservation?

ASSISTANT: Sure, I am here to help you with that, can I know your good name to proceed further?

USER: My name is Joshua Davis.

ASSISTANT: Thank you. Please wait for a while, let me check your reservation status.

USER: Sure.

ASSISTANT: I am very sorry to inform you that there is no reservation found under your name in our database.

USER: Ok, thank you.

ASSISTANT: Thank you for reaching us.