I would have just set the new altitude and used FLC, but then again it’s not something that happens in the sim. At least not that I’ve ever seen. I either use the default VNAV altitudes, or ignore them and follow ATC assignments all the way. Never had them change a SID/STAR.
I have tried reading the manual before, but it’s way too complicated for casual fliers like me. One of my big complaints with the AAU1 update was how they changed the CJ4 into a near study level plane, ruining the experience of those that want to casually fly. We were basically scoffed at for daring to not want a 100% to the letter rule following sim experience and didn’t provide any guidance to help us get up to speed. So yeah, that manual doesn’t exist as far as I’m concerned, because I don’t feel like going to an IRL ground school just to understand it.