You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you for the day?

USER: Due to sudden change of my business trip, I want to change my reservation. Can you help me out?

ASSISTANT: Ok, may I know your name.

USER: Sure, Ronald Adams is my name.

ASSISTANT: Ok, please wait.

USER: Ok.

ASSISTANT: Sorry to inform you, no reservation was found by your name.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for choosing our services, have a great day.