You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Larry Thomas here.

ASSISTANT: How can I assist you?

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

ASSISTANT: Yes, I can help you. Sorry to inform you that there is no reservation found on your name.

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

ASSISTANT: Thank you for contacting us.