Que tal:
$WshShell = New-Object -comObject WScript.Shell
$Shortcut = $WshShell.CreateShortcut("$env:PUBLIC\Desktop\oldapp.lnk")
$oldargs = $Shortcut.Arguments
$Shortcut = $WshShell.CreateShortcut("$env:PUBLIC\Desktop\newapp.lnk")
$Shortcut.TargetPath = "%ProgramFiles%\appdir\app.exe"
$Shortcut.Arguments = $oldargs -replace "server1", "server2"
$Shortcut.WorkingDirectory = "%ProgramFiles%\appdir"
$Shortcut.IconLocation = "%ProgramFiles%\appdir\pic.ico"
$Shortcut.Save()