You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you at this moment?

USER: I am Nancy Thompson here, I want to reserve my ticket from DCA to HOU, can you please help me to book a ticket?

ASSISTANT: Sure, can you please provide your travelling dates to proceed further?

USER: Ok, my respective dates of journey is from 04/17 to 04/19.

ASSISTANT: Wait a moment please.

USER: Sure, I want a direct flight.

ASSISTANT: Nancy Thompson, there are no direct flights available on your provided route.

USER: Ok, no problem.

ASSISTANT: Thank you for contacting us.

USER: Thank you for your valuable time.