In Act 4 of "The Crucible," what happens to Reverand Hale after the Salem witch trials?

In the play, Hale does an about-face and changes his role in the trials.  Originally, Hale is brought in as an investigator who believes that he is doing the Lord's work.  As more and more are arrested, Hale begins to see that greed and revenge are fueling the accusations, not witchcraft.  He decries the trials in Act 3, and in Act 4 we learn he has left Salem for Andover, where the trials have been put to an end.  He returns to Salem only to try to convince some of the accused to confess in order to save themselves.

The real Reverend Hale also began to doubt the veracity of the trials, especially after his wife, Sarah was accused.