How to assign VST symphonic programs to a GM midi file

For studying classical composing i like to replace the GM ( general midi sounds ) programs with the the VSti Symphonic programs
How to do that for a existing midi file … in the list editor …do a program chance ?
Assign a VSti symphonic program to the existing GM midi notes and replace the GM program ?

It should be handy to drag from the Halion Sonic SE program slots a program to the trackheader in the Cubase arrangment.
I will make a testmidi file with a VSti symphonic sound and compare the list editor data from this with the GM file