Agreeing with Bill, but elaborating...
I tend to distinguish between reharmonization and substitution in that subs merely alter the sound of the chord, but the basic harmonic function remains the same. Reharms are changing the chords in such a way that the underlying harmonic function gets changed. (There may be some that don't follow these definitions, but that seems to be how people think of them, even if not in those words.) Of course, there are some that are in a bit of a gray area, but that's life.
Another way to put it is that reharms are more drastic than subs. On the gig, people will be throwing in subs, left and right - either they are trivial and require no musical adjustment or are easy to hear and good players can work with them. Reharms will tend to be more planned out and/or written out. You usually won't do spontaneous reharms on the bandstand, unless they are very common reharms or you are playing with guys with amazing ears. I'll sometimes do spontaneous heharm when I'm doing cho-mel, but obviously that's different.
Peace,
Kevin |