You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

USER: I am Mary Walker. Can you please help me in change my recent reservaion?

ASSISTANT: Sure, please wait a moment.

USER: Ok, sure.

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

USER: Ok, fine thank you for checking.

ASSISTANT: Thank you for approaching us.