You can check this sort of thing on the commandline: usually advisable if you're going to tell someone they got something wrong.

Shaveta_Chawla wants: "... "Smith, Kristen A." should change to "Kristen A. Smith".".

moritz' solution does this:

$ perl -Mstrict -Mwarnings -E 'my $author = q{Smith, Kristen A.}; $aut
+hor =~ s/([^,;]+),([^,;]+)/$2 $1/g; say $author'
 Kristen A. Smith
[download]

Your correction does not do this:

$ perl -Mstrict -Mwarnings -E 'my $author = q{Smith, Kristen A.}; $aut
+hor =~ s/([^,;]+),([^,;]+)/$2, $1/g; say $author'
 Kristen A., Smith
[download]