You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Myself Mary Evans. I would like to change my existing reservation, can you help me in booking?

ASSISTANT: Sure, please wait for a while.

USER: Thank you.

ASSISTANT: Sorry, no reservation found on your given name.

USER: That's ok, no problem. Thank you for the information.

ASSISTANT: Thank you for choosing us.