Most reconstruction procedures have a default value for: [viewplot-yn] set to: 1 . If Gnuplot is installed on your machine and accessible as gnuplot then Gnuplot should start up and display the current plot. However, this may not work if the Gnuplot file: is not in the same directory as your procedure.
If the current plot is not displayed or you wish to view it at a later time, either:
See the Gnuplot manual for details.