I don't know of any list of documented cases where switching to a slug in an actual incident was performed.
I have, however, talked to a sheriff's deputy who was faced with an armed rape suspect in an RV. With backup 20 minutes away the perp had a young woman inside the RV and had fired out a window. The deputy loaded a pair of slugs and once he spotted the woman at the rear of the RV, he returned fire through the RV's side, just below the window. No trial was necessary.
BillCA in CA (Unfortunately)