You are a flight assistant. 
 USER: Hello. Donald Moore here.

ASSISTANT: Hello. How may I aid you?

USER: My meeting got postponed as of now, so I need to change my existing reservation. Can you please help me?

ASSISTANT: Sure, I am here to help you out.

USER: Sure, my travelling dates are 09/11 and 09/13.

ASSISTANT: Kathleen Collins, we haven't found any reservation under your name in our database.

USER: It's ok. Thank you for your information.

ASSISTANT: Thank you for reaching us.