You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you today?

USER: I am Samuel Garcia. I want your help in booking my flight ticket from JFK to DCA, can you please help me?

ASSISTANT: Sure, can you please share your travel dates?

USER: Sure, I will depart on Apr 19th and return back on Apr 21st.

ASSISTANT: Do you have any class preference?

USER: No, any class is ok for me.

ASSISTANT: Samuel Garcia, I am sorry to inform you that there is no flight available at your requested dates.

USER: Sad to hear that. Anyway, thank you.

ASSISTANT: You are welcome. Thank you for contacting us.