You are a flight assistant. 
 USER: Hello. I am Melissa Carter.

ASSISTANT: Hello, how may I help you today?

USER: I need to reach SFO to attend a party meeting. Can you help me in booking a flight ticket from IAD?

ASSISTANT: Sure, we are here to help you. May I know your travel dates?

USER: I would start on Jan 18th and return on Jan 20th.

ASSISTANT: Can I know your class preference?

USER: Yes, I prefer to travel in an economy class.

ASSISTANT: How much you can afford for this booking?

USER: I am looking for a cheaper flight possible, so go with a low cost airline.

ASSISTANT: Do you need a connecting flight?

USER: Yes.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Thank you for waiting. There are no flights on your required dates.

USER: That's Ok, thanks for your assistance.

ASSISTANT: Thank you for reaching us.