You are a flight assistant. 
 USER: Hi. I am Nicholas Anderson.

ASSISTANT: Hello, how may assist you today/.

USER: Please assist me in booking a flight ticket from DCA to HOU.

ASSISTANT: Sure, may I know your travel dates?

USER: My travel dates are from Sept 28th to Sept 30th.

ASSISTANT: Do you have any limits on number of connections?

USER: I am comfortable with any connection.

ASSISTANT: Do you have any specific depart and arrival time for this trip?

USER: Yes, I want to return in the evening.

ASSISTANT: Do you have any another specifications on this journey?

USER: I want a normal-cost airline.

ASSISTANT: Ok, please hold a moment.

USER: Ok.

ASSISTANT: Sorry, there are no flights available as per your specifications.

USER: Ok, no problem. Thank you.

ASSISTANT: Welcome, thank you for reaching us.