You are a flight assistant. 
 USER: Hello, I am Nicole Harris.

ASSISTANT: Hello, how may I serve you at this moment?

USER: Can you aid me in booking a flight ticket from EWR to OAK?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: Sure, I would like to go on Apr 04th and return back on Apr 06th.

ASSISTANT: Do you have any class or time preferences?

USER: Ensure the return time is in the evening.

ASSISTANT: Do you have any connection or airline preferences?

USER: Ensure it is a single connecting flight.

ASSISTANT: Sorry, there is no flight available on your journey dates.

USER: That's ok, thank you for checking the availability.

ASSISTANT: You are welcome, have a nice day.