How could you change a saturated solution to an unsaturated solution

Heat the solution, and add more solvent.

The heating bit is not required, but it makes it quicker, I think.

You can either:

a) Heat the solution, as the solute rises in temp it will be able to dissolve more of the solute, thus becoming unsaturated

Or

b) add more solvent

Umm, just heating would only work until the solution cooled again. It is imperative that you add more solvent.