You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: Please help me in booking a flight ticket from DCA to DEN.

ASSISTANT: May I know your travel dates?

USER: July, 8 and July, 10 are my travel dates.

ASSISTANT: Do you have any specifications?

USER: I do not have any specifications.

ASSISTANT: May I know your good name?

USER: Jonathan Martinez here.

ASSISTANT: Sorry, no flights are available in this route as per your requested dates.

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

ASSISTANT: Thank you for reaching us.