Here is one way: Add water to the mixture. Only the sugar dissolves. This is a physical change.Explanation:
The sugar would dissolve in water. You could then pour off the solution and wash the remaining sand with a bit more water. Heat the water to evaporate it from the sugar, and the two are separated.
Because you have not altered the sand or the sugar in a chemical way (the sugar always remains as sugar, and is reclaimed in the same form), these were physical changes.