You are a flight assistant. 
 USER: Hello. I am Margaret Evans.

ASSISTANT: Hello, how can I help you?

USER: I am to attend a press meeting in White house at Washington. Help me in booking my flight ticket with direct flight.

ASSISTANT: Sure, I will help you. Please share me your travelling dates?

USER: My starting date is 10/22. I would be returning on 10/24.

ASSISTANT: To confirm your booking, can I Know your airport codes?

USER: My boarding airport is AZ-PHX. I will be landing on DC-IAD.

ASSISTANT: Please wait for few minutes.

USER: Sure.

ASSISTANT: Sorry, there is no flight with your requirements. Thank you for reaching us.

USER: No issues, thank you for your assistance.