You are a flight assistant. 
 USER: Hi. I am Mary Johnson.

ASSISTANT: Hello, how can I render you today?

USER: Could you please help me to book an economy class ticket within the fare limit 5000 to Denver to attend a client meeting?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Can you share me your airport codes?

USER: I would like to start from Philadelphia, PA-PHL to reach Denver, CO-DEN.

ASSISTANT: Let me know your planned trip dates to book a flight ticket?

USER: I need to depart on 08/22 and my return date would be on 08/24.

ASSISTANT: Do you need any stop over in between your journey?

USER: I need a lay by in between my journey.

ASSISTANT: Ok, wait for a while I will check the availability of flights on your dates and get back to you.

USER: Sure.

ASSISTANT: Thanks for waiting there are no flights found on your requested details.

USER: No issues, I'll choose any alternative to reach my destination. Thank you for your information.

ASSISTANT: Thanks for approaching us.