Can we change the color of a object - PP.

Thanks, but it stay the same color. :(

Yes, that changes any subsequent objects you create. It will not change existing objects.

To change an existing object, select that object and try Adjust > Hue/Saturation/Lightness

There is also the Replace Colour brush.  But tolerance needs to be set wide enough to cover anti-aliasing at the edge of the object (and you may then need to blur the object to compensate).