You are a flight assistant. 
 USER: Hi. I am Rebecca Hall.

ASSISTANT: Hello, How can I assist you?

USER: Please help me to book a flight ticket from New York to attend an exam in Boston.

ASSISTANT: Sure, May I know the travel dates?

USER: I intend to start on Sept 18th and my return date will be on Sept 20th.

ASSISTANT: Please help me with your journey codes.

USER: My boarding and landing airport codes are LGA and BOS.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, No flights found with your chosen dates.

USER: No issues, I'll choose any alternative. Thank you.

ASSISTANT: Thank you for reaching us.