Editing a date

2 Dates created in a single method

GregorianCalendar now = new GregorianCalendar();
Date currentdate = now.getTime();

GregorianCalendar i = new GregorianCalendar();
i.set(Calendar.MONTH, Calendar.DECEMBER);
i.set(Calendar.DATE, 29);

In a separate method how could I change the "I" date?

Thanks