Rear passenger side got dent how do i replace it

Joko,
You are not very clear on exactly where the dent is. The area behind the side door is called a "quarter panel". These parts are not easily replaced, as they are a welded, structural member of the car's structure. Replacement requires specialized cutting and welding tools, normally only found in auto body shops. If the dent is not to bad, you could try removing the interior plastic trim panels and pushing outward to remove the dent.
Providing that the paint is not damaged and there is not an actual crease in the quarter panel [commonly referred to as a "pop" dent] I would suggest contacting a DENT WIZARD company. They will come to your house and fix the dent, using specialized tools and skills. Do a Google search for PAINTLESS DENT REPAIR including your geographic location in the search to find local companies who can do this work. It's much cheaper than taking the vehicle to an auto body shop.