You can't change it after the fact, you would need to cancel the job and start again with proper settings.
If you did choose the right tray and there is nothing interfering with the selection (Choose paper source by pdf page size in Acrobat/Reader comes to mind) then the driver you have is incorrect, go to Xerox.com and grab a new driver.
Please be sure to select "
Accept Solution" and or select the thumbs up icon to enter
Kudos for posts that resolve your issues. Your feedback counts!
Joe Arseneau
