A convection feature on your toaster oven speeds up the cooking time. This is done via a fan that circulates the hot air around the oven. By moving the air around, you get even heat dispersal and avoid cold spots. Many toaster ovens have two settings; bake or convection bake. This means when reheating pizza slices you have the option to use the convection or not. Either setting will work to get your pizza piping hot. It doesn't take long to heat pizza, so the convection setting offers little advantage for this simple task.
Preheat the toaster oven to 400 degrees Fahrenheit using either the bake or convection bake setting.
Slide the pizza slice onto the rack inside the toaster oven and close the door.
Bake the pizza for between 5 to10 minutes. It may take less time on the convection setting. Watch the slice closely. Remove it when the crust is brown and the cheese is bubbling.
Place the hot slice on a plate and allow it to cool for three minutes before eating.