Yes, but only if you were signed-in when you created the widget. To change the Tracking Id sign-in to http://widgets.amazon.co.uk
and go to the My Widgets section. To change the Tracking Id associated with a widget, you will need to select the Tracking ID that you want from the Tracking Id drop-down in the blue sign-in box in the top left of the page. Then once you have the right Tracking Id selected, simply ‘Edit’ the widget you wish to change and ‘Save’ this widget. It will be updated with the new Tracking ID and all copies you have on your pages will be automatically updated.