It’s preferable to switch the entire body, but I really can’t say whether just switching a few exercises would do the trick. The point of this is to shock the body with completely different parameters so there should be value either way.
On a side note, there’s far more wisdom in training with two different rep schemes throughout the week. One good method is to have 4 workouts per week - two heavy, two light. For example:
Because if you train only high rep for even a month, your strengh will drop drastically! You’ll have a hard time returning to your previous weights when you inevitably reintroduce low reps back into the routine. That’s why I always say that either you include some medium or low reps in the week or just don’t go to high up(like a whole cycle of 12+ reps).
But that’s just me and I worry about maintaining strength.