You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I serve you today?

USER: I am Joseph Hall. I need to attend workshop in Smithsonian Institution at Washington, IAD. Can you please make a reservation from Philadelphia, PHL?

ASSISTANT: Sure, may I know your travelling dates?

USER: My journey dates on 07/31 and 08/02.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: There is no flight available on your route.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you.