Moving food around on a blech

Hi,

If fully cooked food is already atop a blech which covers a heating element on Shabbat, and it is hot, one may move it laterally from a spot which is not actually over the heating element to a spot which is directly over the heating element.

(Rav Moshe Feinstein, Igrot Moshe Orach Chaim 4:74:12)

Have a great day,
Mordechai