"The addition of these Section 25 provisions codifies these “Trip Revisions” and removes the possibility of SUB with OTP options in these instances. CRS can now revise your trip using concrete language in the TA."

Some of this is clear as mud to me. It looks as if substitution has not changed, which appears to be in conflict with a few of the provisions. The substitution section still says that you are to be offered substitution if your trip is cancelled, or there is a change of gauge. So I'm not sure how the out and back and single layover changes can get assigned, without putting you into sub first, which would mean that you could turn it down.

If one of these revisions happens on my trip before show, I think the first call would be to the scheduler, asking if my trip was cancelled, or if there was a change of equipment. If so-put me in sub, and I reject the trip (or accept it, if I want it). After show time, I don't know that you have any choice. But then, I wonder if they can say, "Oh, no, your trip wasn't cancelled, it was just revised. To something completely different." I'm not sure how this wouldn't completely abrogate the substitution section.