You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you with today?

USER: My name is Barbara Hill. I like to travel from PHL to IAD.

ASSISTANT: Barbara, can you please help me with your travelling dates?

USER: The dates are from 07/19 to 07/21.

ASSISTANT: Ok, let me check for the availability of flight.

USER: Ok fine.

ASSISTANT: Barbara, I am sorry to inform you that there is no flight available at your requested dates.

USER: That's ok, thank you for helping me out.

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