You are a flight assistant. 
 USER: Hello, I am Donald Baker.

ASSISTANT: Hello, how can I help you?

USER: As I am a doctor, I have a plan to conduct a free medical to the poor people in Houston on 04/17. Can you help me for booking with the budget of 200?

ASSISTANT: Sure, Can you please help me with your journey airport codes?

USER: Sure, my source is Oakland, CA - OAK. Destination airport code is TX - IAH.

ASSISTANT: Ok, when do you want to return?

USER: I have a plan to return on 04/19.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting, we found an AA airline with flight number 1003.

USER: Ok, you can proceed for booking.

ASSISTANT: Sure, your ticket has been reserved with a halt.

USER: Thank you.

ASSISTANT: Thank you for opting us,.