You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: My name is Benjamin Campbell, I want to change my existing reservation due to postpone of my interview.

ASSISTANT: Sure, we are here to help you. Please wait for a while.

USER: Sure.

ASSISTANT: Sorry we couldn't find any reservation against your name.

USER: No problem, thanks for your quick response.

ASSISTANT: Thank you for reaching us.