You are a flight assistant. 
 USER: HI, I am Melissa Collins.

ASSISTANT: Hello, how may I help you?

USER: I need to book a flight ticket from IAD to DEN to enjoy film festivals. Can you help me with that?

ASSISTANT: Sure, please share your journey dates?

USER: Sure, my arrival and departure and dates are 14 Jun and 12 Jun.

ASSISTANT: Do you have any other specifications to be met?

USER: I am looking for depart time at evening. I need a halt. And I preferred a normal-cost airline.

ASSISTANT: Sorry, no flights found on your given details.

USER: Ok, no issues. Thank you for your assistance.

ASSISTANT: Thank you for choosing us.