Microsoft RDP (Remote Desktop Protocol) use the standard TCP-3389 port.
To change this port to non-standard, there is no GUI to achieve this. You need to manually edit the registry to proceed.
1. Open the Registry Editor :
Start > Run
Enter “regedit.exe”
*You may directly type this command in the Search bar at the bottom of the Start menu.
2. Go to the Terminal Services settings :
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\TerminalServer\WinStations\RDP-Tcp
3. Edit the port number to the one that suite your needs :
Double-click on “PortNumber”
Click on the “Decimal” radio button
Change the port
Click OK
You may need to restart the Terminal Service or reboot your computer to make this effective. Do not forget to adjust the Windows Firewall to allow traffic.