You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Sandra Nelson.

ASSISTANT: How can I assist you today?

USER: I want to book a ticket from AUS to LGA to attend seminar, can you help me in booking?

ASSISTANT: Sure, can you please share your travel dates?

USER: I am departing on 04/17 and return on 04/19.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

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

ASSISTANT: Thank you for contacting us.