You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I guide you today?

USER: I am Christine Mitchell, can you help me for changing my existing reservation, because in my previous reservation I gave wrong airport codes?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Please wait for a minute.

USER: OK.

ASSISTANT: I am sorry to say that there is no reservation found.

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

ASSISTANT: Thank you for reaching us.