These changes are reversible without an application only if the part that is now a flat was, respectively, in either A1 or A2 use immediately before it became a flat.
Mae modd gwyrdroi'r newidiadau hyn heb gais ar yr amod yr arferai'r rhan sydd bellach yn fflat gael ei ddefnyddio at ddefnydd A1 neu A2 cyn hynny.