You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Emily Green.

ASSISTANT: How can I help you?

USER: Can you help me for changing my existing reservation?

ASSISTANT: Just a moment please. I am sorry no reservation found on your name.

USER: Ok, I will wait for your reply. Oh! It's ok, no problem thank you for your services.

ASSISTANT: Thank you for choosing us.