How do I change 2 shallow drawers to 1 deep drawer.

Sounds like something I'd like to tackle. First of all so to your local "Home" store, and check out how much pre-maid drawers cost (if you can get some ready made ones that great. Copy down the measurements to see if they will fit your project. Next, does your drawers have roller type runners? If so you will need to remove every other set of rollers. If they are on wooden runners, you may need to do some sawing.

Next either made your new drawers, and install the roller rails or install the wood rails the distance required to allow the drawers to sit.

Now repeat!

Good luck!!