Could you knock someone out if you hit them in the head with an old-fashioned heavy-bottomed saucepan? Also, assuming the victim was an adult man with a fairly tough head, would he sustain any permanent damage afterwards? (Regardless of whether he was knocked out or just a bit stunned.)
Finally, a kind-of-related question (it's for the same scene, anyway): The character being hit is threatening someone else, who he is holding slightly off the ground by their collar. When he gets hit, would he be likely to let go of them, or would they fall with him?