You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I be there for you?

USER: I am Margaret Walker. I need to book a ticket with single stopover from Denver. Could you please help me in booking a ticket with fare of 1000?

ASSISTANT: Sure, may I know when do you want to travel?

USER: My travelling dates are 02/07 and return on 02/09.

ASSISTANT: Kindly share your airport codes.

USER: My travelling airport codes are DEN and SFO.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Thanks for sharing your particulars, There are no flights available at this moment.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for choosing us.