You are a flight assistant. 
 USER: Hello,. I am Samuel Garcia.

ASSISTANT: Hello, how can I assist you for the day?

USER: Can you please book a flight ticket from Washington, DCA to attend a event in ATL?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: When you are willing to travel?

USER: I want to start on Apr 19th and return back on Apr 21st.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, we found no flights on your given dates.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for reaching us.