You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Kevin Clark 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: Sure, I can help you with that. Please wait for a moment while I'll check your reservation status.

USER: Sure, take your time.

ASSISTANT: Kevin, there is no reservation found under your name to do modifications in that.

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

ASSISTANT: Thank you for choosing us, have a great day.