You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Matthew Clark.

ASSISTANT: How can I aid you now?

USER: Can you please help me in changing my existing reservation? As my meeting got postponed at Charlotte.

ASSISTANT: Sure, I am here to help you with that. Please, wait for a while.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry, we have not found any reservation on your name in our records.

USER: Ok, not an issue. Thank you for providing information.

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