Parsava Parivartini Ekadasi is one among the numerous names of the Ekadashi fasting observed on the 11th day of the Shukla Paksha (waxing phase of moon) in Bhadrapad month (August – September). Parsava Parivartini Ekadasi 2015 date is September 24. It is called Parsava Parivartini because Lord Vishnu who is sleeping during theDakshinayana period turns from left side to right side. This Ekadasi is also known as Jayanti Ekadashi.
Bhadrapad or Bhadra month falls during the Dakshinayana Punyakala and is also the second month in during theChatur Mas period. Popular belief is that the period of Dakshinayana is the night time of Gods. Lord Vishnu is believed to be sleeping during the period.
The Vamana Avatar of Lord Vishnu is believed to have appeared on this day. This Ekadasi is also therefore known as Vaman Ekadasi.
In Gujarat, Parsava Parivartini Ekadasi is observed as Jal Zilani Ekadasi.
Those observe partial Ekadasi fasting on the day as usual skip food items made of grains and rice. Some people opt for complete fast.
Source – http://www.hindu-blog.com/2009/08/parsava-parivartini-ekadasi-2009.html