You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

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

ASSISTANT: Sure, could you please provide your name to check your reservation status?

USER: My name is Rebecca Williams.

ASSISTANT: Ok, 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: Ok, not an issue. May be something went wrong while booking the ticket previously.

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

USER: Anyways, thank you for providing information.