You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how can I provide assistance to you?

USER: I want to visit Houston for a short vacation.

ASSISTANT: Ok, can I know your other journey details?

USER: My travelling days are 12/24 and 12/26. Airport codes are  from CA-LAX to TX-IAH.

ASSISTANT: Ok, may I know your name?

USER: I am William Gonzalez.

ASSISTANT: Ok, give me a minute, I will check the availability of flight.

USER: Ok.

ASSISTANT: Sorry, we could not find any flights for Houston.

USER: Thank you for your service.

ASSISTANT: Thank you for reaching us.