After the drinking of the wine and before beginning the meal, guests at a Shabbat table have the option of washing their hands. Some people traditionally will stay quiet during the washing until the bread has been blessed.

A cup of water is filled and poured over the top and bottom of the right and then left hand.Before wiping the hands dry on a towel, the below blessing is recited.

Barukh atah Adonai, Eloheinu, melekh ha-olam
Blessed are You, Lord, our God, King of the Universe

asher kidishanu b'mitz'votav v'tzivanu
Who has sanctified us with His commandments and commanded us

al n'tilat yadayim.
concerning washing of hands.