You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

USER: I am David Martin. I already have an reservation to attend my meeting, due to some problems meeting place has been changed. So I need a few changes in my reservation.

ASSISTANT: Ok, I will help you in that. Please wait for a while, I will check your reservation.

USER: Sure.

ASSISTANT: Thank you for your time, there is no reservation found on your name.

USER: No problem. Thank you.

ASSISTANT: Thank you for reaching us.