God changes hearts, which is the mind, will, and emotions. It is a work of grace performed by the Holy Spirit within us. Then, God does in us what we could never do for ourselves. We are born again (John 3:6-8). We become a new creation in Christ Jesus (2 Corinthians 5:17). Therefore, all the praise and glory is to God alone.
God changes our mind by the Holy Spirit (Romans 12:1-2). Then we understand the power of the gospel (Romans 1:16). We repent and receive Jesus as our Lord (1 Corinthians 12:3). Repentance means a change of mind. That change is enabled by the Holy Spirit changing our hearts (Romans 2:28-29).
God changes our will with new desires. Before, we had no real desire for Christ. We were unwilling to receive Christ. Now, God has worked in our heart with a desire for Christ (Philippians 2:13). That's the work of God in our heart through the Holy Spirit (Philippians 1:6).
God changes our emotions. Before, we had no tender emotions toward Christ nor remorse for our sins. Now, we have godly sorrow for our sins, and emotions of love and gratitude toward Jesus Christ (1 Corinthians 16:22; 2 Corinthians 7:9-10). That's how God changes hearts.
