Can I change the default RDP port?

Sure, but there are a few things you should keep in mind. Most importantly, if you change the default RDP port, you can no longer connect to your desktop using the Web-based HTML5 viewers. Secondly, to use the new RDP port, you must open the new port on the Microsoft Firewall on your  Cloud Desktop, as well as change the default port used by the RDP client you use to connect to your desktop.