You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Barrbara Robinson here.

ASSISTANT: Yes, Barrbara Robinson.

USER: Can you help me out in ticket booking from IAD to IAH?

ASSISTANT: Sure, can you please help me with your journey dates?

USER: From 08/03 to 08/05.

ASSISTANT: Wait a moment please.

USER: Ok.

ASSISTANT: Sorry to say, there is no flight available on your preferred dates.

USER: Ok. No problem. Thank you to inform me.

ASSISTANT: Thank you for reaching us.