Thawing at room temperature can.

Heating ham slices. After wrapping your ham, place it on a baking tray with the cut side down. Cook or heat the ham as close to serving time as possible. Or use an oven roasting bag;

Follow instructions on the bag for preparation. (place whole ham on its side.) cover. Place slices of ham in a baking pan and cover with aluminum foil.

If heating ham from the freezer, move it to the refrigerator to thaw 24 hours prior. Preheat the oven for about 10 minutes at 325 °f, and place the tray on the middle rack.