You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Jeffrey Johnson.

ASSISTANT: How can I help you at this moment?

USER: I want to travel from AUS to LGA. Can you help me in booking a flight ticket?

ASSISTANT: Sure, I will help you with that. Can you please mention your preferable travel dates?

USER: I want to fly in the flight in May on 21 and 23.

ASSISTANT: Do you have any another specifications?

USER: I want to depart in Evening time.

ASSISTANT: Ok, please wait a moment, I will check flight availability in this route.

USER: Ok, take your own time.

ASSISTANT: Sorry no flights are available in this route as per your requested dates.

USER: That's ok. Anyways, thank you for your help.

ASSISTANT: Thank you for contacting us, have a nice day.