There servername param is the name of your server that host Reporting Services. If the name of the server hosting your resporting services instance is named MyServer then servername = MyServer.
reportserver is the name of your reporting services report server Virtual Directory. by Default this is reportserver.
pathto is the path to your report. I.E. if your report is in a folder called my folder and the reportname is My report pathto = MyFolder%2fMyReport
So given the example you'd use
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