You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I am Nicholas Lee. To attend a science exhibition at Washington DC - DCA, would you please help me to book a direct flight?

ASSISTANT: Sure, we are gleeful to help you for booking. Kindly mention your travelling dates.

USER: My travelling dates are 05/23 and 05/25.

ASSISTANT: Ok, From where do you want to start your journey?

USER: I want to start my journey from Philadelphia, PA - PHL.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for being patient, we found a direct flight in 1013 Frontier airline with a fare of 600. Can I proceed for booking?

USER: Ok, please proceed.

ASSISTANT: Sure, your booking has been confirmed.

USER: Thank you for your assistance.

ASSISTANT: Thank you for approaching us.