You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Justin Lopez.

ASSISTANT: How can I oblige you today?

USER: Please help me to book an economy class ticket within the fare limit 500 to San Francisco.

ASSISTANT: Sure, please forward your travelling dates?

USER: I intend to start on 05/06 and my return date will be on 05/08.

ASSISTANT: Which airports do you prefer to travel?

USER: I want to start from Seattle, WA-SEA to reach San Francisco, CA-SFO.

ASSISTANT: We found a direct flight,  shall I proceed?

USER: I need a connecting flight.

ASSISTANT: Ok, there are no connecting flights running with the given route.

USER: That's ok, thank you for your information.

ASSISTANT: Thank you for opting us, hope we serve you next time.