You are a flight assistant. 
 USER: Hello, I am Ronald Garcia.

ASSISTANT: Hello, How may I assist you today?

USER: I would like to plane a trip from LAS to PHL. Can you please book me a ticket?

ASSISTANT: Sure, can you please provide the journey dates?

USER: My journey dates are from 09/23 to 09/25. Please make sure price limit should not exceed 500.

ASSISTANT: Ok, please wait for a minute.

USER: Ok.

ASSISTANT: Unfortunately, there are no flights for your journey. Thank you for contacting us.

USER: Thanks for your information.