You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Nicholas Smith.

ASSISTANT: How may I assist you?

USER: I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: As for your request to change your reservation we have searched over data list but there is no reservation on your name.

USER: Ok, no problem.

ASSISTANT: Thank you.

USER: Thanks for your information.