"As for Sarai your wife – do not call her name Sarai, for Sarah is her name." (Genesis 17:15)
The name changes of Avram and Sarai recorded in this the book of Bereishis (Genesis) affords us a good opportunity to speak about the significance of a name change in general.The Talmud (Rosh Hashanah 16b) lists four things that can cause an unfavorable decree against a person to be torn up, and one of them is a change of name. How does this work? The Ran is of the view that the function of a name change is to inspire a person to do Teshuva (repentance). The name change helps concretize the idea that henceforth the person must act differently, and that he no longer is the same person as the one who previously committed improper deeds.
The Maharsha offers a different approach in the name of the Yifei Mareh. He argues on the Ran’s notion that the name change is designed to inspire Teshuva. After all, the Torah records (see Rashi to Bereishis 23:1) that at the age of 100 Sarah was as free of sin as a 20 year old!Therefore, we may conclude that her name change was not needed to motivate her to ‘clean herself up’ spiritually. Rather, the significance of a name change – and how it brings about a rescinding of an unfavorable decree – is to bring a change to a person’s Mazal. Once a name has been changed, the Mazal he previously had no longer applies to him, and this is even true when it had been decidedly unpleasant. We see a proof to this from the text of the Torah itself. In the verse immediately following Sarah’s name change (17:18) the Torah records that she – who had been barren for almost 90 years – will now be blessed with a child: “I will bless her; indeed, I will give you a son through her.”
It has been said that a Nafka Minah (practical difference) between these two points of view would arise in the case of a person who is deathly ill (Chas V’Shalom) and medically-speaking not expected to wake up again. Should his name be changed?According to the Ran, the function of a name-change is to inspire Teshuva, so there appears to be no benefit in changing the name in this circumstance. However, according to the Maharsha and Yifei Mareh, the purpose of a name change is to alter one’s Mazal … so in this case the name-change should be attempted!