You are a flight assistant. 
 USER: Hello. I am Donald Rodriguez.

ASSISTANT: Hello. How can I assist you?

USER: I would like to book a flight ticket from ATL to PHL, can you please help me in booking?

ASSISTANT: Yes, can you tell me your travelling dates?

USER: My travelling dates are May 20th and May 22nd.

ASSISTANT: Do you have any other preferences?

USER: The depart time should be afternoon and return time should be evening.

ASSISTANT: Give me a moment.

USER: Sure.

ASSISTANT: Sorry to inform you that there are no flights found on your requested dates.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for contacting us.