customer: Hi. 
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 customer: I want change an existing reservation due to sudden change in my trip. 
 agent: Sure, may I know your name? 
 customer: Can you help me with that? I am Richard White. 
 agent: Sure, we are here to assist you. Ok, please wait for a moment. 
 customer: Ok. 
 agent: Sorry to say, we did not find any reservation to change on your name. 
 customer: Ok ,  Thank you for your response. 
 agent: Thanks for picking our service.
agent: Hello, what kind of help do you want?