Open the drawer. If you can see the slide, you have a side-mount. If the slide cannot be seen, look underneath and verfiy that it is mounted underneath.
Disconnect the side mount drawer slide by pulling the drawer from the cabinet. Locate the two black locking levers inside the runners. Press them down and remove the drawer.
Press the release clips located on the bottom of the drawer on the under mount slides. The clips are mounted on both sides. Press the clips simultaneously and release the drawer from the cabinet.