You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

USER: I am Lisa Edwards. I am planning to celebrate my birthday in Houston, so please book a flight ticket from AUS to IAH.

ASSISTANT: Sure, I am happy to help you with that. Can you please share your preferable journey dates?

USER: I will start on May 07, return on May 09.

ASSISTANT: Do you have any class preference?

USER: No, I am comfortable with any class.

ASSISTANT: Is there any class preference?

USER: I am already provided.

ASSISTANT: I am sorry to say that there is no flight found under your details.

USER: No problem, thank you.

ASSISTANT: Thank you for reaching us, have a great day.