In act 4 of The Crucible why does John call for the judges after his discussion with Elizabeth?

In the conversation you are talking about John Proctor has been condemned to death for witchcraft.  He is talking to his wife Elizabeth about whether he should give a false confession so as to avoid being executed.

After they finish talking, John decides that he will confess.  Once he has decided, he tells Hathorn and Hathorn is the one who calls for the other judges.

As it turns out, John confesses, but then thinks better of it and rips up his confession after thinking about what confessing means and after talking briefly with Rebecca Nurse.  As the play ends, he is being executed.