You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Helen Roberts.

ASSISTANT: How may I assist you at this moment?

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

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Please wait a moment to check your previous reservation. We regret to inform you that there is no reservation found on your name in our records.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for reaching us, have a great day.