Repentance means more than sorrow at having been found out. Regret is not repentance. Repentance involves a turning from and a turning to. You can turn from, but not turn to. Indeed the prodigal could have determined on his own to clean up without ever going home and that is what a number of people do. They try to clean up their lives. They engage in all kinds of religious pursuits, but there is still no transformation.
It is possible to maintain a sense of wretched Independence (staying away from God) while all the time seeking to turn from our sins, (i.e., I am prepared to admit what I did was wrong and that I am in a royal mess, but I will not go back and face my father). I will not go back and admit what I have done. All the prodigal’s regret allied with his own independence would have left him in a great predicament. Self-righteous moral reparation is not the same as repentance. It is absolute hypocrisy to want forgiveness of sins without deliverance from sins. It is not repentance, but it is disappointment at having been discovered.
What then shall we we do? In Luke 3:10-10 the crowd asks Jesus what they should do. And the crowds asked him, “What then shall we do?” 11 And he answered them, “Whoever has two tunics  is to share with him who has none, and whoever has food is to do likewise.” 12 Tax collectors also came to be baptized and said to him, “Teacher, what shall we do?” 13 And he said to them, “Collect no more than you are authorized to do.” 14 Soldiers also asked him, “And we, what shall we do?” And he said to them, “Do not extort money from anyone by threats or by false accusation, and be content with your wages.” 15 As the people were in expectation, and all were questioning in their hearts concerning John, whether he might be the Christ, 16 John answered them all, saying, “I baptize you with water, but he who is mightier than I is coming, the strap of whose sandals I am not worthy to untie. He will baptize you with the Holy Spirit and with fire. 17 His winnowing fork is in his hand, to clear his threshing floor and to gather the wheat into his barn, but the chaff he will burn with unquenchable fire.”18 So with many other exhortations he preached good news to the people. 19 But Herod the tetrarch, who had been reproved by him for Herodias, his brother’s wife, and for all the evil things that Herod had done, 20 added this to them all, that he locked up John in prison.21 Now when all the people were baptized, and when Jesus also had been baptized and was praying, the heavens were opened, 22 and the Holy Spirit descended on him in bodily form, like a dove; and a voice came from heaven, “You are my beloved Son;  with you I am well pleased.”
The evidence of repentance is a changed life. If we repent, our lives will bear fruit that befits repentance. Repentance will show amendment especially in avoiding sin. Failing to repent is proof of spuriousness. It is especially hard in any profession to oppose its common practices, which always elicits ridicule perhaps even persecution by the impenitent. Hence the avoidance of sin is a good test of repentance. In the end, seeing the Gospel lived out far surpasses talking about it. Each station in life has it’s peculiar temptations and sins. Repentance turns from sin and turns to Christ. Without holiness no one will see the Lord. Without sincere repentance, we will never meet Jesus in this life or the life to come.
As Jesus says in Luke 17, And he said to his disciples, “Temptations to sin  are sure to come, but woe to the one through whom they come! 2 It would be better for him if a millstone were hung around his neck and he were cast into the sea than that he should cause one of these little ones to sin.  3 Pay attention to yourselves! If your brother sins, rebuke him, and if he repents, forgive him, 4 and if he sins against you seven times in the day, and turns to you seven times, saying, ‘I repent,’ you must forgive him.”