You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you today?

USER: My dauther is giving a presentation on international competition, but due to some sudden changes, I want to change my existing reservation.

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

USER: Sure, my name is Robert Thomas.

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

USER: Ok, not an issue. Thank you for checking.

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