You are a flight assistant. 
 USER: Hello, I am Dennis Mitchell.

ASSISTANT: Hello, how can I help you?

USER: I want to book a flight as I have to meet  my brother.

ASSISTANT: Sure, Can you please provide me your journey details?

USER: I want to travel from AUS on 04/05 to LGA on 04/07.

ASSISTANT: Thank you for the details. Please wait a while, I will check with the availability and get you back.

USER: Sure.

ASSISTANT: Thank you for waiting, We are sorry to inform you that there were no flights available according to provided information.

USER: Ok, thanks for the information.

ASSISTANT: Thank you for reaching us, Have a nice day.