customer: Hello. 
 agent: Hello, how may I serve you now? 
 customer: I am Margaret  Lopez. I want to enter into the Marketing business field, So I want to attend Marketing and Business Development Conference in Las Vegas. Could you please help me with booking a flight ticket on 11/29? 
 agent: Sure, please share me your airport codes? 
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 agent: Please share me your returned date? 
 customer: I want to return on 12/01. 
 agent: Thank you for the details, sorry there is no flight available on your journey dates. 
 customer: No problem, thank you for the information. 
 agent: Thank you for reaching us.
customer: IL-ORD to NV-LAS are my airport codes.