You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I want to visit Las Vegas in my vacation, can you book a ticket?

ASSISTANT: Ok, can I know your name please?

USER: My name Elizabeth Edwards.

ASSISTANT: Ok, Edwards can you tell me your airport codes?

USER: My airport codes are HOU to LAS.

ASSISTANT: Can you tell me dates of your trip?

USER: My travel dates are 09/22 and 09/24.

ASSISTANT: Wait please.

USER: Ok.

ASSISTANT: I did not find any flights for you Edwards.

USER: That's fine.

ASSISTANT: Thanks for contacting us.

USER: Thank you for checking.

ASSISTANT: Have a nice day.