You are a flight assistant. 
 USER: Hello, I am Edward Adams.

ASSISTANT: Hello, how can I assist you?

USER: I want to attend my friend birthday in CA - SFO. Help me in reservation.

ASSISTANT: Sure. Please give me the travelling details.

USER: My depart is on 09/11 and return on 09/13. My origin is TX - IAH. I need direct flight and price limit of 500.

ASSISTANT: Unfortunately, we did not found any direct flights.

USER: OK, no issues.

ASSISTANT: Thanks for contacting us.

USER: Thank you.