customer: Hi. 
 agent: Hello, how can I help you? 
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 agent: May I know your desired travel dates please? 
 customer: Sure, my travelling dates will be 01/21 and 01/23. 
 agent: Please wait a while. 
 customer: Ok. 
 agent: Sorry to say, there is no flight on your desired travel dates. 
 customer: That's ok, thank you. 
 agent: Thank you for opting us, have a nice day.
customer: I am Betty Walker want to visit IAD, can you book a ticket from OAK?