You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Cynthia Garcia.

ASSISTANT: How may I help you today?

USER: I need a flight ticket booking from LAS to OAK to attend a client meeting, can you please help me with flight ticket booking?

ASSISTANT: Sure, I am here to help you in booking process. can you please share your travel dates?

USER: Thank you for accepting my request and my travel dates are 19 and 21 in the month of May.

ASSISTANT: Do you have any class preference?

USER: No.

ASSISTANT: Sorry, no flights are available on your preferable travel dates.

USER: Very sad to hear that, I can prefer any other source. Thank you for your help.

ASSISTANT: Thank you for opting us, have a nice day.

USER: Welcome.