You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How could I serve you today?

USER: Could you please book me a flight ticket from ORD to SFO?

ASSISTANT: Sure, may I know your travelling dates?

USER: I will start on May 31st and return on June 2nd.

ASSISTANT: Do you need any other requirements?

USER: I need 1 flag stop within my route.

ASSISTANT: Can you please share me your name?

USER: I am Helen Miller.

ASSISTANT: Unfortunately there is no flight found with your given information.

USER: That's alright, thanks for your response.

ASSISTANT: Thank you.