You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: David Moore here.

ASSISTANT: How can I assist you for the day?

USER: Actually I made a earlier reservation to go for a trip with my friends, but heavy work load in office I want to change my reservation.

ASSISTANT: Sure, I am mirthful to help you with that reservation change. Please wait for a while, let me check your previous reservation status.

USER: Ok.

ASSISTANT: Thank you for waiting. There is no active reservation found with your name in our reservation list to change it.

USER: That's ok, thank you.

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