You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Pamela Mitchell.

ASSISTANT: How can I assist you?

USER: I want to attend a meeting at Houston, can you please book a ticket on 12/29?

ASSISTANT: Sure, can I know your airport codes?

USER: My source is at Los Angeles, CA-LAX and destination is at Houston, TX-IAH.

ASSISTANT: Please share your return date also.

USER: My arrival date is on 12/31.

ASSISTANT: Please give me a minute.

USER: Ok.

ASSISTANT: Pamela, there is no flight available on your requested dates.

USER: Ok, no problem. Thank you.

ASSISTANT: You are welcome.