You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you at this moment?

USER: Can you please help me in changing my reservation?

ASSISTANT: Sure, may I know your name to check the reservation status?

USER: I am Susan Hall.

ASSISTANT: Ok, please wait for a minute.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name to change.

USER: No problem, thank you.

ASSISTANT: Thank you for choosing us.