Rename and/or move a file on the FTP server.
First available in version 3.0 build 2039.
existingFile - The name of an existing file on the FTP server to be renamed.
newFile - The new name of the file.
No output parameters.
When this method is called synchronously, a return object containing the output parameters is returned to the caller immediately.
The existingFile and newFile parameters can be relative to the current directory or absolute paths.
If the existing file and newfile parameters have different paths, a move as well as a rename will be performed. If you specify "/public/myfiles/readme.txt" as the existingFile and "/public_html/readme2.txt" as the newFile, then readme.txt will be renamed to readme2.txt and moved to the "/public/html" directory.