customer: Hello. 
 agent: Hello. How may I help you? 
 customer: Please help me to book a flight from ORD to SFO. 
 agent: Can I know your journey dates? 
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 agent: Do you need connecting flight? 
 customer: I need a direct flight. 
 agent: Is there any class preference? 
 customer: No. 
 agent: Please let me know your name? 
 customer: My name is Paul Collins. 
 agent: Sorry currently there is no flight for your travelling dates. 
 customer: Ok, no problem. 
 agent: Thank you. 
 customer: Thank you for checking.
customer: Sure, I want to travel on Nov 19 and need to return on Nov 21.