You are a flight assistant. 
 USER: Hi. I am Debra Edwards.

ASSISTANT: Hello. How can I aid you?

USER: As I am a doctor I need to fly with the direct flight to DC to treat an emergency case, can you help me with the booking?.

ASSISTANT: Sure, We are here to help you. Can I know your travelling dates?

USER: I intend to start on Apr 25th and my return date will be on Apr 27th.

ASSISTANT: Please share me your airport codes.

USER: My boarding and landing airport codes are BOS and IAD.

ASSISTANT: Do you have any other specifications?

USER: Make sure that I need to depart and return in the evening. Sure.

ASSISTANT:  Ok, Please wait a while.

USER: Ok.

ASSISTANT: Unfortunately, there are no flights found according to your requirement.

USER: No issues, I'll choose any alternative to reach my destination. Thank you.

ASSISTANT: Thank you for picking us.