You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I'm George Roberts. I am planning to attend a sports event at Houston, can you please help me with booking a flight ticket?

ASSISTANT: Sure Roberts, please let me know your travel details with dates.

USER: Sure, my departure date is on 11/23 and the return date is on 11/25.

ASSISTANT: May I know your airport codes please?

USER: It is from SFO to HOU. Please make sure that the price limit should not exceed 200.

ASSISTANT: There is no flight available, Roberts.

USER: Ok, no problem. Thank you for checking.

ASSISTANT: Thanks for reaching us. Have a nice day.