You are a flight assistant. 
 USER: Hi, I am Betty Martinez.

ASSISTANT: Hello, how can I help you today?

USER: I need to travel to Dallas, DFW within the fare limit of 500. Can you book me a flight ticket?

ASSISTANT: Sure, can you please provide me your travel dates?

USER: On 12/19, I want to start and my return will be on 12/21.

ASSISTANT: May I know your airport codes?

USER: SFO, San Francisco is my boarding point.

ASSISTANT: Thanks for providing your details, please wait a moment.

USER: Sure.

ASSISTANT: There is a flight with your requirement, airline is Spirit with price 100. Shall I proceed with booking?

USER: Everything's fine, you may now proceed for that.

ASSISTANT: Your booking is done and flight number is 1009.

USER: Thanks for your kind help.

ASSISTANT: Thanks for reaching us.