Jayapataka Swami: You find in the Srimad Bhagavatam in the history of Ambarisa Maharaj and others that there was a particular time to break the fast. You had to break the fast at that time. So we also follow that that there is a parana time and we try to break the fast during the parana period. When I was in LA, after my stroke, I was doing some physiotherapy, one day was Ekadasi and the parana for that the next day was one minute! So they called me and when that minute came, I immediately broke the fast! But usually it is like, 6 am to 9 am or 7.30 to 10.30 am. So we have ample time to break our fast. But sometimes it is very short. That is calculated by the astrologers and so whatever the time is, we try to break our fast in that time. If someone breaks fast accidentally in the middle, then  Srila Prabhupada would  say that he would have to observe the fast again on Trayodasi. On Dvadasi we shouldn’t fast. Day after Dvadasi, again we do the Ekadasi fast or by doing the Pandava Nirjala Ekadasi that counts for all the Ekadasis in the year. So if we miss some Ekadasi you may also do the Nirjala, but we also observe every Ekadasi the no grain, cereal, pulse.