You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Jeffrey Turner.

ASSISTANT: Is there any help that you need from my side?

USER: As my plans to visit Dallas got postponed, can you please help me by changing my existing reservation?

ASSISTANT: Sure, I am happy to help you. Please give me a moment for checking.

USER: Thank you.

ASSISTANT: When I have checked there is no reservation found for the user name to modify your previous booking.

USER: Ok, not an issue. May be something went wrong while booking the ticket previously. Thank you for providing information.

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