You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you today?

USER: Could you please help me to update my travelling dates in my existing reservation?

ASSISTANT: Sure, we are glad to help you.

USER: Thank you.

ASSISTANT: On whose name, you want to update the dates?

USER: Sure, I am David Hall.

ASSISTANT: Ok, wait for a while.

USER: Sure.

ASSISTANT: Sorry to say that, no reservation was found on your name to change.

USER: That's ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for availing us.