ABC
1
original listSmith, Miller, Patty, Smith, Patty, Miller
2
reduced listSmith, Miller, Patty
3
formula=JOIN(", ",UNIQUE(TRANSPOSE(SPLIT($C$1,", "))))
4
5
sorted listMiller, Patty, Smith
6
formula=JOIN(", ",SORT(UNIQUE(TRANSPOSE(SPLIT($C$1,", ")))))