You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I am Amy Perez, can you help me to book a flight ticket from Houston, HOU to Washington, DCA?

ASSISTANT: Sure, will you mention your travelling dates please?

USER: Ok, my depart date is 05/31 and return date is 06/02.

ASSISTANT: Please give me a moment.

USER: Ok. Please book a direct flight.

ASSISTANT: Thanks for waiting, there is no flights found under your preferable details.

USER: Thank you for helping me. That's ok, I will book next time with new dates?

ASSISTANT: Welcome, have a great day.