How To Change Value Of Boolean Within A Method

I read in a book that when you change the value of a method parameter that's a boolean or other basic datatype within the method it only is changed within the method and remains the same outside. I want to know if there is some way for me to actually change it within the method. For example:

public class Change {
void convert(boolean x, boolean y, boolean z) { //i want to set x,y, and z to false in this
x = false;
y = false;
z = false;

[code]...

I want to put in part1, part2, and part3 when i call the method than i want them to be set to false within the method. The specific reason i asked this question was because im trying to code a battleship and i have a subroutine class with a method that when its called it checks if a ship has been sunk. If the there was a sink than the method will set a ton of boolean variables to false.

Just to clarify, I want something like this:

void convert(thing1,thing2,thing3,thing4) {
//some code here that sets thing1,thing2,thing3, and thing4 to false
}
// than in main:
boolean test1 = true;
boolean test2 = true;

[code]....