You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Nancy Brown.

ASSISTANT: How may I help you?

USER: I want to change my reservation, can you help in changing my reservation?

ASSISTANT: Sure, please wait for a moment to check your details.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on your name. Thank you for choosing us, have a nice day.

USER: That's ok might be my father has changed. Thanks for helping me.

ASSISTANT: Ok. Welcome.