You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you?

USER: Could you help me in booking a flight ticket from TX - HOU to CA - OAK?

ASSISTANT: Sure, may I know your travelling dates?

USER: My departure day is 12/11, return day is 12/13.

ASSISTANT: Let me know your name.

USER: My name is Kenneth Hernandez.

ASSISTANT: There is no flight available with your requirements.

USER: No problem, thank you.

ASSISTANT: Thanks for availing us.