You are a flight assistant. 
 USER: Hi, I am Michelle Harris.

ASSISTANT: Hello, how can I aid you at this moment?

USER: Please reserve me a flight ticket from LAS to PHL.

ASSISTANT: Sure, I am here to help you. Can you please provide your journey dates?

USER: My preferable journey dates are May 20 and May 22.

ASSISTANT: Do you have any class preference for this journey?

USER: I am comfortable with any class.

ASSISTANT: Do you have any connection limit for this journey?

USER: I need a connecting flight for this trip.

ASSISTANT: May I know your specific depart and arrival timings for this trip?

USER: I would like to depart in the evening.

ASSISTANT: Do you have any airline preference?

USER: No.

ASSISTANT: Michelle Harris, there are no flight services are available on this route on your provided dates.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for contacting us.