You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: My name is Sarah Martin. My business meeting was postponed, so I want to change my existing reservation.

ASSISTANT: Sure, we will help you to change your reservation. Please wait for a couple of minutes.

USER: Sure.

ASSISTANT: Thanks for waiting, we did not find any reservation on your specified name.

USER: No problem, thanks for your help.

ASSISTANT: Thank you for choosing us.