You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: David Perez here.

ASSISTANT: How can I help you today?

USER: As I am a musician, I have to attend my concert on 11/21 at Phoenix.

ASSISTANT: Ok, can you please help me with the airport codes?

USER: Yes, my airport codes are from HOU to PHX.

ASSISTANT: Could you please provide the return date?

USER: I want to return on 11/23.

ASSISTANT: Ok, let me check for the availability of flight.

USER: Ok.

ASSISTANT: David, there is a flight available at your request with price 100. Would you like me to proceed the booking?

USER: Please proceed.

ASSISTANT: Sure. Your booking is confirmed.Your flight number is 1008 with UA airline.

USER: Thank you for helping me.

ASSISTANT: You are welcome. Thank you for contacting us.