HOW TO PERFORM AVANI AVITTAM ( SACRED THREAD FUNCTION)

 1. Kamo Kaarsheed Japam
Early in the morning after sandya vandanam/samitha daanam(for bachelors only) Kamo Karsheeth Japam is performed for 1008 times, to relive one of the deeds/sins done with or without one's knowledge and to get oneself ready for the maha sankalpam, .. and finally the Vedharambam.
2. Maha Sankalpam
This is a social / community activity, where all the brahmans gather on a river bank and do the sankalpam for getting rid of all the sins, etc.. and they mention different rivers, Gods, templs etc.. to specify their geographical location and then whether it be Caveri / Vaihai / Krishna they have a shower. After this everyone wears silk or new clothes (if available), etc.. and get ready for the grand ceremony.
3.Yagnopaveetha Dharanam
This is to rejuvenate and refresh one's spiritual energy and make oneself, eligible for the Veidc (Sroutha,Smartha Nithyanushtana Yogyatha) rituals , one changes the sacred thread and removes the old one saying it is old, broken (jeernam, kasmala, dhooshitam). There are 2 achamanams prescribed for this, - one for wearing a new poonal and another for removing the old one.
4. Kandarishi Tharpanam
Kanda rishis represent the rishis or sages for each chapter or kandas in the Vedas (Soma,Agni,Prajapathi, ..) and each of those Vedic rishis are given water / rice (tharpanam). People, who do not have their father alive, also do pithru tharpanam and thus this ritual ends.
5. Kandarishi Homam
In places where they do it elaborately with a Purohitar, they also do this, by first chanting Punyaha Vaachanam, and then invoking all the Kanda rishis, 7 rishis (Athri...) in the kumbam and then, invoking all of them int he fire and offering havis, kshana dandam (mixture of all fruits..,appam,sundal..) and offering it in the fire. after that Jayadi homam is performed.
6. Vedarambam
Officially, the Adhyayanam or Vedic classes start with vedarambam and critical lines /s tanzas (like Agni Meelee..) are chanted + Maheswara Suthram, etc... After this the rishis are thanked, offered naivedyam, karpooram.. and everyone, disperses tot heir homes, chanting the Vedas.
This is a more than 20000 years old tradition, which is preserved until today.
The first step is a 'prayashchita', A prayer to atone the sins. It says, "For the removal of all my sins and thereby to secure a divine blessing and for qualifing myself to perform the essential duties of Brahmanas as prescribed in the vedas and smritis and adopted by the really good in their conduct I put on this Yagnopavita (the sacred thread).
Then a new Yagnopavita is worn. When the thread is worn another mantra is recited which means -"I put on the sacred thread which is highly pure, is inseparable from God, is capable of prolonging life and is the foremost in the accomplishment of a Brahmana. May such pure Yagnopavita bring strength and dignity."
While removing the old thread, the mantra means -"I throw away the broken dirty old thread, may the new one bring on long life and Brahmana's brilliance."

Procedure of Avani Avittam

• First the Rishi Tharpanam (offering prayers to the ancient Rishis) is read out.

• Brahmin bachelors perform 'Samitha Daanam' and 'kamo karshith japam' after Mahasankalpam.

• Thereafter, Kaanda Rishi tharpanam is performed with the help of family priest or elders.

• As per the rituals, all the male members should have a light meal at night.

• Next day after an early bath, 'Gayathri Japam' is read out by everyone. Thereafter, Appam & Idli are served.

• Green Gram, Dhal or Kondai Kadalai Sundal are offered as Neivedhyam for the Homam (Fire ritual).

• The Homam is performed either in the house or in temples and the Arti is performed after everyone returns home.

• Naivedyam - Payasam, Vada, Gingely seeds, Rice. The other items that are served on this day are Curd Pachadi, Kosumalli Curry, Koottu, Pitlay, buttermilk, soup, rasam, dhal and chips, appalams.

Inner meaning

This day is also auspicious as the Brahmins offer libations of water to their ancestors to whom they owe their birth and to the great Rishis to whom they are highly indebted for spiritual knowledge and the Vedas themselves

For further reference please contact  http://www.hindu-blog.com/2007/08/significance-of-avani-avittam.html