Symbol Schematic
The Symbol tab of the component/symbol properties set-up dialog allows selection of the hierarchical schematic attached to that symbol. This is accessed by double-clicking on the symbol.
Attaching Hierarchical Schematic with New Symbol
Selecting a new schematic using the browse buttons of the symbol tab dialog will automatically create a copied new symbol and place it in the UserSymbols folder. The schematic will be updated to reflect this new location for the symbol. This is to allow for the original symbol to be used with any schematic.
Attaching Hierarchical Schematic With Existing Symbol
To change the schematic of an existing symbol without creating a new symbol it must be done via the Symbol Manager. Right click on the symbol in the symbol folder, and use the properties menu item to pop up the symbol manager. Use the "Select Schematic" button to navigate to a new schematic file.