You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Cynthia Baker here.

ASSISTANT: How can I aid you today?

USER: Reserve a flight ticket that is for my airport codes from IAD to SFO. The price limit is less than 200.

ASSISTANT: Ok, I'll do that for you. Can you please share your respective travel dates?

USER: The travel dates are from 09/23 to 09/25.

ASSISTANT: Spirit airlines is having a flight on that route with travel charge of 100, shall I proceed for booking?

USER: I am happy with the airlines. You can book the flight ticket.

ASSISTANT: I have successfully booked your ticket with flight-1005, have a safe journey.

USER: Thanks for booking my flight ticket.

ASSISTANT: Thank you for choosing us.