You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I provide assistance to you?

USER: I am Donna Martinez and I want to book a flight ticket to Philadelphia, PA-PHL to take a part in trekking at Evans mountain, can you help me to book a flight ticket?

ASSISTANT: Sure, I will help you. How much can you afford for a flight ticket?

USER: I can pay up to 500.

ASSISTANT: From where you want to travel?

USER: My boarding point is Denver, CO-DEN.

ASSISTANT: Could you please share your journey dates to process your reservation?

USER: I intend to return on 03/30 and my plan to start on 03/28.

ASSISTANT: Ok, please wait a while.

USER: Sure.

ASSISTANT: Thanks for your time, we did not find any flight with your requirements.

USER: Ok, no issue.

ASSISTANT: Thank you for reaching us.

USER: Thank you.