pressing some more until you are in the correct year (if necessary) in the leap year cycle and correct month within that year. Then keep pressing some more. Once the watch has the right date, press the day only button to get to the right day. See the manual (paragraph 1) for more precise details on the day and date settings. If you’re thinking that this is all a little nuts, you are probably right😊 (Or if you acquire one, might be best to take it to a Patek service center and let them do it Personally, I would be concerned about doing it myself and again see the recommendation in paragraph 3 in the manual.)