You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Charles Miller here.

ASSISTANT: Is there any help that you are expecting from my side?

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 in flight ticket modification. Please wait for a moment. Thank you for waiting, I have checked based on your request and it is showing that there is no reservation found for the user name in our data base.

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

ASSISTANT: You are most welcome.