One way 

my $nth = 3;
my $rep = 1;
my $chr = 'e';
my $i = 1;
$_ = "Terence and Philip are sweet";
s/($chr)/$i++<$nth?$1:$rep/eg;
print;

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In reply to Re: Replacing a given character starting with the xth occurence in a string by quent
in thread Replacing a given character starting with the xth occurence in a string by Anonymous Monk

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