You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: Can you please help me in changing my existing reservation?

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

USER: Joshua Davis here.

ASSISTANT: Ok, please hold on a moment.

USER: Sure.

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

USER: No issues, thank you.

ASSISTANT: Welcome Joshua Davis.