Preheat the oven to 275°F
Remove the ham from packaging and place it cut side down in a roasting pan
Cover the ham tightly with foil
Heat for about 10 to 12 minutes per pound, or until warmed through
If using a glaze packet, warm it slightly if needed
Remove the foil during the last 10 to 15 minutes of heating
Brush or spoon the glaze over the ham
Return the ham to the oven uncovered to caramelize the glaze
Check that the internal temperature reaches 140°F
Remove the ham from the oven
Let it rest for 10 to 15 minutes before slicing
Slice and serve