You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Will you help me to book a flight ticket from LAX to DEN?

ASSISTANT: Your travelling dates please?

USER: I will start on May, 9 and return on May, 11.

ASSISTANT: Do you have any connection limit?

USER: I would prefer single connection.

ASSISTANT: Is there any other specifications?

USER: My return time should be at afternoon.

ASSISTANT: There is a flight with single in United airlines, can I proceed for booking in 1012 flight?

USER: Please proceed.

ASSISTANT: On which name can I proceed for booking?

USER: Karen Harris.

ASSISTANT: Your booking is done in economy class.

USER: Thank you.

ASSISTANT: Thank you for choosing us.