You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I am very interested in trekking so I heard Wisdom Tree is the one of the place for trekking in Los Angels. So, can you help me in booking my flight ticket from Oct 29 to Oct 31?

ASSISTANT: Yes, can you tell me your nearest airport codes?

USER: Yes, my nearest airport codes are LAS and LAX.

ASSISTANT: Give me a moment.

USER: Sure.

ASSISTANT: Sorry to inform you that there are no flights found on your requested dates.

USER: Not a problem, anyways thank you for the information.

ASSISTANT: Can I know your name for documentation?

USER: Yes, I am Mary Walker.

ASSISTANT: Thank you for contacting us.

USER: You are welcome.