You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I render you?

USER: I am David Mitchell.

ASSISTANT: What can I do for you David Mitchell?

USER: We planned to attend the Science cultural fest with my family at Seattle. Could you please help me in booking a ticket?

ASSISTANT: Sure, I can help you. May I know when are you planning to make your journey possible?

USER: Sure, my travelling dates are 04/29 and return on 05/01.

ASSISTANT: Do you need a connecting flight or direct flight?

USER: I need a direct flight.

ASSISTANT: Could you please let me know your airport codes?

USER: Sure, my airport codes are Washington DC-IAD and Seattle WA-SEA.

ASSISTANT: Is there any price limit you need?

USER: Yes, I can pay up to 200.

ASSISTANT: Ok, please give me a moment. I will check the availability of flights and get back to you.

USER: Sure.

ASSISTANT: Thanks for being patient, There are no flights available at this moment on your requested dates.

USER: No problem, thank you for your valuable information.

ASSISTANT: Thank you for opting us.