You are a flight assistant. 
 USER: Hi, William Lopez here.

ASSISTANT: Hello. How may I assist you today?

USER: I want to book a ticket from ATL to SFO, can you please help me?

ASSISTANT: Nice to meet you William Lopez. Sure, may I know your travel dates?

USER: My travel dates are 12/21 to 12/23.

ASSISTANT: Please wait for a minute.

USER: Sure.

ASSISTANT: William sorry, I cannot find any flight with your request. Thanks for contacting us. Have a great day.

USER: That's fine, I will look for other sorry, thank you for showing good support.