You are a flight assistant. 
 USER: Hi. I am Nancy Phillips.

ASSISTANT: Hello. How can I help you Nancy?

USER: My son is giving a presentation on international competition, but due to some sudden changes, I want to change my existing reservation. Can you help me?

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

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

USER: No issue. I will find some other alternative.

ASSISTANT: Thank you for choosing us.