When we have a rise thats too long, to deep, too high, what ever you wish to call it, its a major alteration. The waist band is removed along with the lining and thr belt loops. As much as one inch can be cut off the top pof the trouser. Cutting off more than that would interfere with the side pockets. Then the waist is reconstructed . the dotted line at the top is where the waist band is sewn back on. One inch difference in the rise is a large amount. Manufactures trouser rises change 1/2" between short and regular and also between regular and long. When the rise is too short and needs to be lengthened, the work is done at fork. see the dotted line at the bottom of the rise thats the new sewing line. The excess cloth is then cut away.