You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello. How can I help you?

USER: I need to attend my sister's marriage. So please help me with reservation. I want the ticket with name David Smith.

ASSISTANT: Could you please send me your journey details?

USER: Sure, my starting point is Las Vegas, NV- LAS and ending point New York, NY- EWR. My depart date is on 15th April and return date is on 17th April.

ASSISTANT: Please wait a while.

USER: OK.

ASSISTANT: Thanks for being patient. Unfortunately,there are no flights found as per your specifications.

USER: OK, no issues. Thank you for the information.

ASSISTANT: Thank you.