Here is a quick batch file which does what you are asking for
[
copy or print]
@echo off
if %1.==. goto USAGE
if %1.==. goto USAGE
if not exist %1 goto NOTEXISTS
if not exist %2 goto NOTEXISTS
REM move first to temp name
set tempfile=%1.%RANDOM%
move %1 %tempfile% > NUL
move %2 %1 > NUL
move %tempfile% %2 > NUL
goto EXIT
:USAGE
echo USAGE: swap file1 file2
goto EXIT
:NOTEXISTS
echo ERROR: Can't find the file(s) you specified
:EXIT
echo.
Obviously since it's a batch file it would flash in a command prompt window, but you can hide it by creating a shortcut and setting the program status to minimized. You can then drop either the shortcut or the batch file to your sendto folder, at your convenience

Just copy/paste the code to a text file (notepad) and save it as swap.bat or swap.cmd and you're set
bye