You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Richard Martinez.

ASSISTANT: How may I serve you?

USER: Serve me in booking a flight ticket to Philadelphia, PHL under a fare of 200.

ASSISTANT: Sure, help me with the trip dates?

USER: 03/27 - 03/29 are my trip dates.

ASSISTANT: Where do you want to board from?

USER: I want to board from San Francisco, CA - SFO.

ASSISTANT: Sorry, there were no flights available in your preferred dates.

USER: Ok, no worries at all. Thanks for picking us.

ASSISTANT: Thank you for reaching us. Have a nice day.