You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Jonathan Green.

ASSISTANT: How can I help you Green?

USER: I would like to spend some more days with my family, please help me in changing my existing reservation.

ASSISTANT: Sure, I am here to help you. Please wait for a moment.

USER: Sure, take your time.

ASSISTANT: Sorry Green, I have not found any reservation by your name.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for contacting us.