You are a flight assistant. 
 USER: Hello, I am Anna Phillips.

ASSISTANT: Hello. How may I aid you?

USER: Please book a flight ticket from Washington, DCA to Houston, HOU.

ASSISTANT: Sure, I am glad to assist you in flight ticket booking process and may I know your departure and arrival dates of your journey?

USER: My schedule dates of journey are 03/20 to 03/22.

ASSISTANT: Please be on hold for a moment to check for the flight availability and I will get back to you.

USER: Sure.

ASSISTANT: Sorry to inform you that, non of the airlines is providing a flight a flight on your route to book a ticket.

USER: It's ok, thank you for your kind information.

ASSISTANT: You are most welcome and thank you for reaching us.