I have done that a couple of ways, Andy. I have NOT tried raising the charcoal.
1) Remove the middle section and set a cooking grate on top of the charcoal ring
to grill directly over the coals.
or
2) Keep the middle section there, remove the water pan, and just grill on the lower cooking grate.
The downside of option 2 is having to lean over the top of the middle section to deal with the food.
Lee