"Steven Barnes" wrote:
I'm working on my ifr. I've always been confused with this part about
"once the pilot starts descent and verbally reports leaving an altitude in
the block, he may not return to that altitude without additional ATC
clearance."

I'm thinking, why report leaving an altitude? That just restricts what you
can do later. Or at least makes you ask for it back. What would make the
pilot verbally report leaving an altitude in the block?

For the same reason people cancel IFR once they have the airport in
sight. It frees up some airspace for somebody else to use. You're not
required to do so, but it's part of being a good IFR citizen.