You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I am Frank Collins, can you help me to book a flight from IAH to DCA?

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

USER: I am willing to travel on 08/09 and return on 08/11.

ASSISTANT: Please give me a moment.

USER: Ok, take your time.

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

USER: That's ok, not a problem. Thank you for assisting me.

ASSISTANT: Welcome, have a great day.