You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: Can you please help me in booking flight ticket to SFO from ORD?

ASSISTANT: Sure, please provide your travelling dates.

USER: My travel dates are from Jan 21 to Jan 23.

ASSISTANT: Ok, Do you have any class preference?

USER: I need a economy class ticket.

ASSISTANT: Ok, May I know your connection limit?

USER: I would like to travel in connecting flight.

ASSISTANT: Ok, Is there any other preferences?

USER: No.

ASSISTANT: Ok, May I know your name?

USER: I am David Baker.

ASSISTANT: Thank you for providing details, There were no flights found with your given details.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for choosing us.