You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

USER: Mark Robinson here. Due to heavy rains cricket match got postponed, so I need to change my existing reservation.

ASSISTANT: Sure, please wait a moment.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: That's ok, thank you for informing.

ASSISTANT: Thank you for approaching us.