You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

USER: I am Carolyn Nelson. Can you help me for changing my existing reservation, because I gave wrong airport codes in my previous reservation?

ASSISTANT: Sure Nelson, please wait a moment.

USER: Ok, I will wait for your reply.

ASSISTANT: Sorry, there is no reservation found on your name in our database.

USER: Oh! It's ok, no problem. Thank you for your services.

ASSISTANT: Thank you for choosing us.