You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I'm Stephanie Carter.

ASSISTANT: How can I assist you?

USER: My holiday trip has been postponed.So, I would like to change my existing reservation. Can you please help me with the changing the reservation?

ASSISTANT: Sure, give me a minute?

USER: OK.

ASSISTANT: Sorry to say that there is no reservation found.

USER: That's OK. Thank you for the information.

ASSISTANT: Thank you for contacting me.

USER: You are welcome.