Rigvedis - Aashwalaayana sub-sect (Pakazhiyan)

As one gets ready for the mid-diurnal prayers (Upasththaanam) after doing the necessary ablutions, aachamanam and prokshanam, take the new thread in the left hand and sprinkle water ritualistically on oneself and on the thread. Then, face the east, hold the thread stretched and away from the body between the two thumbs, mentally chant the Pranavam ten times looking at the sun, and put the thread on with the right hand. Then do the arghyadaanam and continue with the mid-day prayers. Finish the Tharpanam, wash the feet and perform the Aachamanam. Take off the old thread, wind it round a small stone and throw it away into the body of water. Wash the feet and do the Aachamanam again.

If changing the thread before or after the Upasththaanam, wear the thread as instructed above, recite Gaayathri, do an Arghyadaanam, and perform the Tharpanam turning clockwise. Then follow the instructions above.

Rigvedis - Kausheethaka sub-sect

Rituals are no different from Aashwalaayanans, but there is just one Manthram to be chanted before putting the thread on.

Om.	"Yajnasyopaveethena upavyayaami Deerghaayuthwaaya, suprajaasthwaaya, Suveeryaaya, sarveshaam vedaanaam Aadhipathyaaya, yasase brahmavarchasaaya thwaam"

Yajurvedis – Baudhaayana sub-sect

After the prayers reciting "Om. Ghrinisooryadithya:", put on the thread reciting the Manthram.

Om.	"Yajnopaveetham paramam pavithram Prajaapather yath sahajam purasthaal Aayushyamagryam prathimuncha subhram Yajnopaveetham balamasthu theja:"

Take water in your hands and chanting
"Om. Aapojyotheeraso mritham brahma bhoorbhuvassuva: Om"
turn clockwise and perform Tharpanam. Wash the feet, perform Aachamanam, dispose off the old thread in the water, wash feet and perform Aachamanam again.

If the changing of the thread is not along with Uupasththaanam, wash the feet, do Aachamanam and Prokshanam, make a proffering to the Sun, recite Gaayathri ten times not omitting Chchandas, complete the Chchandas, do a punararghyadaanam, and put on the thread reciting the Manthram. Everything else is the same as for Rigvedis above, except that there is no need for the Upasththaana Manthrams.

Saamavedis

Wash the feet and perform Prokshnam (for both self and the thread). Sit on the sitting board (Aavanappalaka) facing east, hold thread by the thumbs, chant Pranavam 108 times not omitting the Chchandas. Get up and put the thread on. Wash the feet, do Aachamanam and Prokshanam and finally Tharpanam turning clockwise. (Mind not to omit the Chchandas)

If changing the thread along with Upasththaanam, go ahead with arghyadaanam and mid-day rituals after putting it on. Get rid of the old thread in the water by tying it around a stone after propitiating all three Sandhyaas

Auspicious days for changing the thread

The thread can be renewed on any weekday except Tuesdays and Saturdays. Because wearing the thread is indispensible, even these two days are not taboo if there is an emergency like when the thread is broken or has become unwearable. So in case of an emergency renewal, a proper follow-up renewal at the nearest auspicious time is recommended. In case of any problem with the ritualistic twist-threading of the sacred thread, one should at least wear a makeshift pro tem thread by roughly twisting three strands together.