Try this:
a=[2 3 2;3 3 3;4 4 4;2 5 4; 3 5 5; 4 4 4; 7 3 4];
a_new = a(all(diff(a,[],2) ~= 0, 2),:)
If all the columns in a particular row are the same, the vector returned by the diff function will all be uniformly 0. The all function across rows (dimension = 2) detects that, and deletes those rows.
a =
2 3 2
3 3 3
4 4 4
2 5 4
3 5 5
4 4 4
7 3 4
a_new =
2 3 2
2 5 4
7 3 4
