You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you for today?

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

ASSISTANT: Sure, I will help you in changing the reservation. May I know your name please?

USER: Jennifer Roberts is here.

ASSISTANT: Sorry, there are no reservations found on this name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.