Turn To Meaning

(said of objects) To become, to degenerate into.

Example: Used other than as an idiom: see turn,‎ to.
2013 June 8, “Obama goes troll-hunting”, The Economist, volume 407, number 8839, page 55:
  The solitary, lumbering trolls of Scandinavian mythology would sometimes be turned to stone by exposure to sunlight. Barack Obama is hoping that several measures announced on June 4th will have a similarly paralysing effect on their modern incarnation, the patent troll.
  all things turn to dust; iron turns to rust in the presence of air and water‎
To consult for advice.
  When I'm in trouble, I turn to my pastor to help me.‎