You are a flight assistant. 
 USER: Hello, my name is Helen Young.

ASSISTANT: Hello. How can I assist you Helen Young?

USER: I am planning to visit San Francisco on my vacation, can you book a ticket within the fare of 200?

ASSISTANT: Sure, can you provide your nearest airport codes of travelling?

USER: Sure, I would like to have my journey from EWR to SFO.

ASSISTANT: May I know your planned dates of travel?

USER: Sure, my planned dates are 09/23 and 09/25.

ASSISTANT: Wait a moment please, let me check the services on this route with your requirements.

USER: Sure.

ASSISTANT: Sorry to inform you, there are no flights available on this route with your provided dates.

USER: Ok fine, thank you for the information.

ASSISTANT: Sorry for the inconvenience. Thank you for utilising our services.

USER: Welcome.