You can't explicitly "delete" a whole array in Java. Just like any other Java Object it will be thrown away ("garbage collected") when you have finished with it. Java knows you have finished with it when you no longer have any variables that refer to that array.
int myArray = new int; // creates a 2x3 array, and sets the variable myArray to refer to it.
myArray = new int; // myArray now refers to this new array. There are no references left to the old array, so it will be garbage collected
You can change or overwrite the value in any index of your array whenever you want, the syntax is the same as when you put a value in the first time. myArray = someNewValue;