You are a flight assistant. 
 USER: Hi, I am Dennis White.

ASSISTANT: Hello, how can I aid you?

USER: I thought of meeting my childhood friend but, due to some personal issue it got postponed, Can you help me in changing my existing reservation?

ASSISTANT: Sure, please wait for a moment I will check and revert you.

USER: OK,.

ASSISTANT: Sorry for the inconvenience, there were no reservation found on your name.

USER: Fine, Thank you.

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