You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Brandon Lopez here.

ASSISTANT: How may I help you?

USER: I have a conference meeting at San Francisco. Could you please help me in booking a ticket from ATL to SFO.

ASSISTANT: Lopez, I am here to help you. When you planning to travel?

USER: My planned travel dates are 12/11 and 12/13.

ASSISTANT: Just a moment.

USER: Sure, take your time.

ASSISTANT: Lopez sorry for inconvenience, no flights are available with your requirements.

USER: Ok, no issues. Thank you for your information.

ASSISTANT: Thank you Lopez for contacting us.