You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you today?

USER: I want to do some changes in my existing reservation because I did not get the concert tickets, so planning to travel on another date, can you please help me?

ASSISTANT: Sure, I can help you. May I know your name please?

USER: Sure, my name is Nancy Lee.

ASSISTANT: Lee, I have not found any reservation under your name.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for contacting us, have a great day.