my $counter = 0;

if ( $_ =~ /unassigned/ ) {
    $_ =~ s/.*\n//gi; #delete unassigned line
    $counter++;    #count will be 1 and will be caught by next if statement
}
if ( $counter = 1 ) {
    $_ =~ s/.*\n//gi;  #delete next line
    $counter++;    #count will be 2 and will be caught by next if statement
}
if ( $counter = 2 ) {
    s/.*\n//gi;    #delete the 2nd line after unassigned
    $counter = 0;    #make count to 0 until $_ is something you are looking for
}