What does 'repent ' mean ?

My understanding is that repentance simply means ' change of mind ' .
It could also be breaking frame from a current set of propositions.

Jesus gives an example of repentance being a change of mind in Mathew 21 .
28¶But what think ye? A certain man had two sons; and he came to the first, and said, Son, go work to day in my vineyard.
29He answered and said, I will not: but afterward he REPENTED AND WENT.
30And he came to the second, and said likewise. And he answered and said, I go, sir: and went not.
31Whether of them twain did the will of his father? They say unto him, The first. Jesus saith unto them, Verily I say unto you, That the publicans and the harlots go into the kingdom of God before you.
32For John came unto you in the way of righteousness, and ye believed him not: but the publicans and the harlots believed him: and ye, when ye had seen it, repented not afterward, that ye might believe him.
So we see two things . He repented ( changed his mind and went . So repenting isn't the action its the changing of mind .