You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

USER: I am Robert Lee. I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Sure, I am please to help you.

USER: Thank you.

ASSISTANT: Please stand by I will get back to you.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry to say no reservation found on your name.

USER: Ok, no problem. Thanks for your information.

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