You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Rebecca Scott.

ASSISTANT: How may I assist you, Scott?

USER: Due to my ill health, I would like to postpone my trip to Dallas. Can you please help me by changing my existing reservation?

ASSISTANT: Sure Rebecca, please give me a minute.

USER: Sure, take your own time.

ASSISTANT: Rebecca, there is no reservation found with your details.

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

ASSISTANT: Thank you for contacting us.