An insert for repositioning at least one of the harness straps of a child safety seat in order to accommodate an occupant smaller than the harness is configured to accommodate, wherein the insert is adapted to locate between the child safety seat and the occupant and includes a pair of waist strap guides, each waist strap guide configured to allow a waist strap of the harness to extend through and exit the waist strap guide at a position narrower than where the waist strap exits the child safety seat.