You can only have one UberMenu per page, but you can have multiple UberMenus on your site, provided they never occur on the same page. The real limiting factor to the number of UberMenus you can have is your number of Theme Locations.
Please keep in mind that settings in the UberMenu Control Panel are global, so while you can have different menu contents on different pages, they will all share the same orientation, animations, styles, etc.
To easily swap out different menus on specific pages, you can use my free Menu Swapper plugin. This plugin allows you to register new theme locations and then change out the theme location on any Page, Post, or Custom Post Type in WordPress (it won’t help on archive or taxonomy pages), without having to write any code.
Are you looking just to change individual menu items on a specific page, or within a specific category? Check out the UberMenu Conditionals Extension