You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Stephen Hall.

ASSISTANT: How can I assist you today?

USER: Can you help me in changing my reservation, as my meeting is postponed?

ASSISTANT: Sure, please give me a moment.

USER: Ok.

ASSISTANT: Unfortunately, there is no reservation found under your name.

USER: Thank you for your time. No problem.

ASSISTANT: Thank you for reaching us.Have a great day.