You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Frank Hernandez.

ASSISTANT: How can I help you?

USER: I am planning to visit Los Angeles to meet my father, can you please help me in booking a flight ticket from IAD to LAX?

ASSISTANT: Sure, I will help you to book a flight ticket. Can you please share me your travelling dates?

USER: My travelling dates are Sep 22 and Sep 24.

ASSISTANT: Please wait a moment. Sorry, there are no flight tickets available at your location.

USER: That's ok, thank you for checking.

ASSISTANT: Welcome, have a nice day.