You've already gotten the answer to your question, but I'd like to point out one thing.

You will get better performance if you do:

my $date1 = Date::Manip::Date->new;
my $date2 = $date1->new_date();
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If you're working with lots of dates, there will be cached data that allow you to achieve much better performance, and by creating the 2nd (and other) dates from the first, the cached data is shared, so they all benefit from it.