You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: Sarah Campbell here. I need to change my recent reservation because my conference meeting was postponed.

ASSISTANT: Sure, please wait a moment I will check your details and proceed further.

USER: Sure, take your own time.

ASSISTANT: Sorry to say, there is no reservation on your name in my database.

USER: It's ok, not a problem.

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