Hello Guytrance,
I'm not sure what exactly are you trying to accomplish here. As you probably know Centova Cast depends on Apache to access it's web interface, so to change the port for Centova Cast it will mean changing the port where Apache listens as well. Which will also change the port where all your web applications listens (not just Centova Cast), unless ofcourse your other control panel is self contained, then you simply have to change your Apache configuration to listen on a different port.
Hope this helps.