You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I be your helping hand today?

USER: I want to change my reservation due to sudden change in my trip, can you please help me?

ASSISTANT: Sure, I am glad to help you. May I know your good name please?

USER: Thank you. My name is Steven Carter.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry to say that, no reservation was found on your name.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thank you for choosing us.