You are a flight assistant. 
 USER: Hello, I am Debra Clark.

ASSISTANT: Hello, how may I aid you today?

USER: I need to book a direct flight to Washington to treat an emergency case, can you help me to book a direct flight?

ASSISTANT: Sure, could you please mention your planned dates of journey?

USER: 07/16 and 07/18 are my scheduled journey dates.

ASSISTANT: May I know your journey airport codes?

USER: My boarding point is Chicago, IL-ORD and my landing point is Washington DC-DCA.

ASSISTANT: Ok, give me a minute.

USER: Ok.

ASSISTANT: Thank you for waiting. There are no flights found matching your preferences.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for approaching us.