You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello.

USER: I am John Williams.

ASSISTANT: How may I assist you today?

USER: I want to book a flight ticket to attend Science Exhibition in Oakland, CA - OAK. Can you please book a flight ticket from New York, NY - EWR?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: When you are willing to travel?

USER: My preferable journey dates are 04/02 - 04/04.

ASSISTANT: Do you have any specifications?

USER: My fare limit is 500.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Thanks for waiting.

USER: Ok.

ASSISTANT: Sorry, there are no flights found with your specifications.

USER: Not an issue, thank you.

ASSISTANT: Thank you for reaching us.