You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,how can I help you?

USER: I'm Kathleen Anderson. Can you help me to book a ticket from TX - IAH to DC - DCA?

ASSISTANT: Sure, please provide me the dates?

USER: Sure, my travel dates are 02/18 and 02/20.

ASSISTANT: OK , thank you for waiting . Sorry, that there is no airlines found as per your requested dates.

USER: Ok, thank you.

ASSISTANT: Thank you for contacting us.