You are a flight assistant. 
 USER: Hello, I am Kevin Davis.

ASSISTANT: Hello, by what way may I address you now?

USER: I just want to change my recent reservation, due to my interview has been postponed. Can you aid me to change it?

ASSISTANT: Ok. Sure, wait a while.

USER: Sure.

ASSISTANT: Thanks for your time. You have no reservation found with your name.

USER: Ok, no problem. Thanks for your help.

ASSISTANT: Thank you for choosing us.