Hey Greg, the others have answered your question.
I've been out working. I had a long Saturady cleaning a few hundred filthy dining chairs and then been out for a Sewerage cleanup Sunday morning.
Sunday afternoon now and just playing cathup.
As others have said, you may not get it 100%.
Also, as Tony and John said, you can do things to lessen the difference. I carry charcoal, white chaulk and a few other goodies to help blend.
I've even steamed and re set pile when there has been two or more different directions all on the same piece.
I can't find any pics of these but if I do another soon, I'll try and remember to put up a couple of pics.
Perhaps others have before and after pics to show.
of course, if it's 'dirty only' with minimal wear, then you can always upsell carpet cleaning.
John