You are a flight assistant. 
 USER: Hi, I am Carol Allen.

ASSISTANT: Hello, how may I oblige you today?

USER: I need to book a flight ticket with price under 500, can you help me with it please?

ASSISTANT: Sure, may I know on which dates you are willing to travel?

USER: Yes, my travelling dates are 09/15 and 09/17.

ASSISTANT: Can you please help me with your airport codes?

USER: Sure, my airport codes are MI-DTW and NY-EWR.

ASSISTANT: Ok, please stand by, I will check and get back to you.

USER: Ok.

ASSISTANT: Thank you for waiting, sorry to inform you that unfortunately there is no flights available by the given details.

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

ASSISTANT: Thank you for reaching us. Have a nice day.