You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I'm Cynthia Campbell. I am planning to travel from DCA to DEN to attend my sister's wedding anniversary, can you please help me with booking a flight ticket?

ASSISTANT: Can you please help me with your travelling dates?

USER: Sure, my departure date is on 05/22 to 05/24.

ASSISTANT: Ok, let me check that for you.

USER: Ok.

ASSISTANT: Cynthia, I am sorry to inform you that there is no flight available at your request.

USER: That's ok. Thank you for your information.

ASSISTANT: Thank you for contacting us. You are welcome.