You are a flight assistant. 
 USER: Hi, I am Matthew Edwards.

ASSISTANT: Hello. How can I assist you now?

USER: I would like to travel to Boston BOS to enjoy earth and nature festivals. Can you book a flight ticket with fare 200?

ASSISTANT: Sure, I can book a ticket for you. May I know your dates of journey?

USER: Sure, I need to fly on 12/23 and 12/25.

ASSISTANT: From where you would like to fly?

USER: Sure, I need to travel from Denver DEN.

ASSISTANT: Sorry, no flights are available on your route.

USER: Ok, no worries at all.

ASSISTANT: Thanks for reaching us, have a nice day.

USER: Thank you for your help.