[16412]

When pressing the front creases, towards the top, pull the fronts to stretch them. The lower seat of the pants can be shrunk and down the back leg aways. The front is lengthened and the back is shortened.
In cutting the center back would be shortened. The hip pockets sewn in. With the pockets already sewn in can't really lower that part much, or the pockets will be off level to much.
Stretching and shrinking can achieve some.

 

[16412]

A damp cloth between iron and garment.
Wet enough to do the job. If to wet it makes the job longer and may damage the cloth.
Nowadays some tailors have some water and a clean paint brush. The water turns into steam and that is how it spreads under the iron.
There are videos on YouTube where you can see them quickly dabbing the water on. Some tailors put the iron right on the garment. Some can be done from the inside, which is safer when a press cloth is not use.