1) Start Registry Editor by typing regedit at command prompt.
2) Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\TerminalServer\WinStations\RDP-Tcp\PortNumber
3) On the Edit menu, click Modify, and then click Decimal.
4) Type the new port number, and then click OK.
5) Quit Registry Editor.
6) Restart the computer.