You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I am Katherine Miller. Due to sudden changes in the weather, I was fallen sick my meeting has been postponed.So I would like to change my existing reservation.

ASSISTANT: Ok.

USER: Could you please help me?

ASSISTANT: Sure, We are here to help you. Please wait a minute.

USER: Sure.

ASSISTANT: Thanks for waiting. There is no reservation found on your data.

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

ASSISTANT: Thank you.