Physics: How to change center of mass?

Tried to modify Center point, tried to modify origin, but I can’t find a way to change objects, center of mass. I kinda need it for my project. Any help?

Trying doing this:
Open your sprites in a paint program. Then using that program, centre your image on the centre of mass you wanted. Then change your sprites in gd and change the collision mask to match the body. See if this works.
Note: Use paint .net, its a good software and might help you a lot. Also when changing the sprites, the position of these sprites might get displaced and either you have to change the origin or position in according to the already given origin

That wouldn’t work, object still wouldn’t rotate down when it is falling (and not, I don’t have object on “fixed rotation”).

Could you just show me the gdg(please put some images too- doesn’t matter if you give me some altered sprites)