In the Talmud, Rosh HaShana 16b Rabbi Yitzchak said: Four things cause the unfavorable decree against a person to be torn up: Tzedaka (charity), Tzeaka (crying out), Shinui Hashem (change of name) and Shinui Maaseh (change of action).
Where do we learn this from?
In Mishlei (Proverbs) 11:4 concerning Tzedaka it says “And charity will rescue from death.”
In Tehilim (Psalms) 107:28 on the topic of Tzeaka we read: “They cried out to God in their distress and He would take them out from their straits.”
Breisheet 17:15 speaks about Shinui Hashem: “Sarai your wife, you shall not call her name Sarai, for Sarah is her name.” After her name was changed, Sarah was blessed with a son.
In Jonah 3:10 we see Shinui Maaseh: “God saw their deeds that they repented from their evil way. God relented concerning the evil He had said He would bring upon them and He did not do it.”
We too can attempt to overturn an unfavorable decree by increasing our charitable contributions, crying out to God in prayer and changing our ways.
Changing your name should not be taken lightly but in some cases is necessary. For example, people who were not born Jewish or those becoming more observant who were never given a Jewish name should take on a Hebrew name when they commit to Judaism the way that Avraham and Sarah did. Others may not be happy with their given name and may decide to choose a new name and formally have their name changed in the synagogue with a Mishaberach prayer during Torah reading. According to the Rambam some need to change their names in order to break from the past and make a fresh start.
There is also a concept of adding a new first name to the name of a person who is very sick to help bring about a speedy recovery. Names that are often used are Chayim, Chaya (life) or Refael (healing).
As we prepare for Rosh HaShana we can’t just sit back and wait for the new year. We must do everything that is in our power to overturn any unfavorable decrees. As it says in the Unetane Tokef prayer: U’Tshuva, U’Tefila U’Tzedaka Maavirin et Ro’ah Hagzeirah, Repentance, Prayer and Charity annul the evil decree.