You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you?

USER: I am Laura Smith. I planned to attend for a wedding in DEN, can you please help me to book a flight ticket from IAD?

ASSISTANT: Sure, can I know our preferable dates?

USER: I planned to travel on 11/26 and 11/28.

ASSISTANT: I am sorry, there are no flights available.

USER: Ok, not an issue.

ASSISTANT: Thank you, have a good day.

USER: Thank you for your information.