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

ASSISTANT: Hello, How can I amend you today?

USER: Please book a flight to Los Angeles,LAX.

ASSISTANT: Sure, we are here to aid you. Help me with your origin airport?

USER: I was invited to visit the Hollywood sign, so I am going from New York, EWR.

ASSISTANT: When your willing to travel?

USER: I am planning to travel on 12/20 to 12/22.

ASSISTANT: Thanks for sharing your details.

USER: Ok.

ASSISTANT: There is no flight found to your route. Thank you.

USER: Ok, I will check with other alternative. Thank you.