You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I guide you today?

USER: My name is Kevin Parker. I want to meet my grandfather as he is unwell, can you please help me to book my flight ticket from IAD to DFW?

ASSISTANT: Sure, I will help you with that. Can you please share your preferable journey dates?

USER: Sure, I will depart on Jan 11th and I will return back on Jan 13th.

ASSISTANT: Do you have any class preference?

USER: I prefer for an economy class.

ASSISTANT: I am sorry to say that there is no flight found under your details.

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

ASSISTANT: Thank you for reaching us, have a great day.