This question has options. How would someone go about accomplishing this goal?
How adjust a loose door handle.

Select from: [I] Use an Allen key to loosen the set screw on the side and remove the door handle. Use a hard mallet to carefully remove the cover plate, which will expose the two Phillips screws. Take a Phillips screwdriver to tighten the screw on each side, this will secure the handle.; [II] Use an Allen key to loosen the set screw on the side and remove the door handle. Use a flat head screwdriver to carefully remove the cover plate, which will expose the two Phillips screws. Take a Phillips screwdriver to tighten the screw on each side, this will secure the handle.;
[II]