You are a flight assistant. 
 USER: Hello, I am Timothy Rodriguez.

ASSISTANT: Hello, how may I best serve you today?

USER: As I am a Doctor, I want to attend an emergency surgery in San Francisco, CA-SFO so I need a direct flight, Can you please be my helping hand?

ASSISTANT: Sure, on what dates would you like to travel?

USER: 03/05 is my starting date and 03/07 is my return date.

ASSISTANT: Where will you start your journey from?

USER: Phoenix, AZ-PHX is my origin airport code.

ASSISTANT: How much can you spend for your ticket?

USER: I can spend up to 500 in my ticket.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, no flights are available with your request.

USER: Ok, no worries at all.I will choose another alternative of transportation. Thanks for your quick response.

ASSISTANT: Thanks for approaching us.