You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you at this moment?

USER: I am Jessica Martinez. Can you please book a flight ticket from SFO to LAX?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: Sure, I need to travel on dates of 12/05 and 12/07.

ASSISTANT: Can I have a moment please? I  will check the availability.

USER: Sure, take your time.

ASSISTANT: Sorry, there is no flight available on your required dates.

USER: Oh! It is sad to hear. Anyway, thank you for your time.

ASSISTANT: You are welcome, have a nice day.