You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: My name is Charles Lewis. I want to book a ticket to meet my friend in Philadelphia, will you help me with booking ticket from LAX to PHL.

ASSISTANT: Yes, can I know your travelling dates?

USER: The travel dates are from 12/29 to 12/31.

ASSISTANT: Ok, give me a moment. Sorry to say that there are no flights found matching your requirement.

USER: That's really sad.

ASSISTANT: Thank you for reaching us.

USER: Most welcome.