You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: My name is Jack Wilson. My concern is to change the reservation which I had done last week, can you help?

ASSISTANT: Sure, just a moment please. I am sorry no reservation found on your name.

USER: Ok, I will wait. Thank you for assisting me, I will check my mails to know more.

ASSISTANT: Thank you for choosing us.