Change Xerox Printer Paper Source

You can change the paper source on the Xerox copiers to print with the overflow/different trays with this process:

Open the print dialog with Ctrl+P or File > Print on the document that you'd like to print.
Locate the "Print using system dialog" button/link on the print window
Go to "more settings" on the system print dialog.
When the Xerox printing preferences dialog appears, under the "Printing Options" tab, select the drop down under "Paper". This will show the different paper types in the printer and you're able to choose which one you would like to print with.