The Chapter you need to look at to find the moment of change for Patria that transforms her from a good, law abiding citizen who will not support the rebel movement to a woman who is willing to oppose Trujillo's regime comes in Chapter Eight. This clearly is a moment of transition for Patria, as she observes the slaughter and capture of some rebel soldiers by government forces that completely changes her opinion of her role in the resistance. Note how Patria explains her transformation:
He was a boy no older than Noris. Maybe that's why I cried out, "Get down, son! Get down!" His eyes found mine just as the shot him him square in the back. I saw the wonder on his young face as the life drained out of him, and I thought, Oh my God, he's one of mine!
It is this identification that Patria feels with this young soldier with one of her own children that makes Patria leave this experience "a changed woman," carrying the dead boy as if it were her son. This is when Patria feels she can no longer sit back and watch her country being treated in such a terrible way by Trujillo:
I'm not going to sit back and watch my babies die, Lord, even if that's what You in Your great wisdom decide.
From this point on, Patria is a committed member of the rebel movement, joining her other sisters in their opposition to Trujillo.