You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Michael Lee.

ASSISTANT: How may I guide you today?

USER: I want to book a ticket from DCA to DFW, can you help me?

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

USER: My travel dates are Oct 01 and Oct 03.

ASSISTANT: Do you have any class preference?

USER: I want to travel in economy class.

ASSISTANT: Is there any connection limit?

USER: I need a connecting flight.

ASSISTANT: Do you have any specifications?

USER: I want to depart in the evening.

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

USER: No problem, thanks for checking.

ASSISTANT: Thank you for reaching us.