Modify Residential Floor Plan in AutoCAD

I have an existing residential house floor plan in AutoCAD DWG format along with a PDF/reference drawing. I need an experienced AutoCAD 2D drafter to make several modifications to the existing drawing. I do NOT need a new design from scratch. The work will mainly involve: Modifying existing walls and room layouts Adjusting dimensions and positions Copying/repeating existing elements between floors where required Making stair/layout modifications Adding or removing small drawing elements as instructed Keeping the existing drawing structure/layers as much as possible Maintaining accurate dimensions and alignment Delivering the final editable DWG