You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: Can you please book a flight ticket from DCA to DFW?

ASSISTANT: Sure, may I know your travel dates?

USER: I want to travel in Feb from 1st to 3rd.

ASSISTANT: Please share me your name.

USER: I am Melissa Allen.

ASSISTANT: Do you have any specifications?

USER: Yes, I need a connecting flight with a seat in economy class.

ASSISTANT: Sorry, there is no flight at this moment.

USER: That's ok, thank you for your information.

ASSISTANT: Thank you.