You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: As my meeting got postponed at Dallas, can you please help me in changing my existing reservation to Dallas?

ASSISTANT: Sure, I am here to help you out. Please provide me your name.

USER: My name is Donald Lee.

ASSISTANT: Sorry. Lee, I didn't find any reservation on your name in our database.

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

ASSISTANT: Thank you for reaching us.