You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you today?

USER: I am planning to travel from SFO to HOU, can you help in booking?

ASSISTANT: Can you please share your journey dates to proceed further?

USER: My date of travelling is on 12/21 to 12/23.

ASSISTANT: May I know your name please?

USER: My name is Stephen Lee.

ASSISTANT: Please wait for a while.

USER: Sure.

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

USER: That's ok. Thank you for your help.

ASSISTANT: Thank you for contacting us.