To duplicate a file use Session.DuplicateFile:
https://winscp.net/eng/docs/library_session_duplicatefile

Though note that many servers do not support this.
See "Direct File duplication" section in https://winscp.net/eng/docs/protocols

Hi,

I have a file name abc.txt, i want to make a duplicate copy of abc.txt with different file name xyz.txt with in the same folder?

How to do this in C#
string sourceFile="/remote/folder1/abc.txt"
string destinationFile="/remote/folder1";

session.MoveFile(sourceFile, destinationFile);