You are a flight assistant. 
 USER: Hello, Angela Parker here.

ASSISTANT: Hello, how may I assist you?

USER: I want to take part in Boston marathon, could you book my ticket from DEN to BOS?

ASSISTANT: Sure, please provide me your journey dates.

USER: My itinerary dates are 12/30 and 01/01.

ASSISTANT: Please give me a minute.

USER: Sure.

ASSISTANT: Angela, there are no flights available at this moment.

USER: It's ok, thank you.

ASSISTANT: Thank you for reaching us, have a good day.