The short version:-
You can’t change this*.
The long version:-
All replicator clones work in steps, and have no concept of steps per unit. That is handled either in your slicer, or in the post-processor GPX that many slicers use to convert from GCODE to X3G for the printer. When GPX sees a GCODE telling it to extrude a certain length of filament, it does the sums with it’s internal steps-per-mm and outputs an X3G code which tells the printer how many steps to run the extruder motor.
* is technically a lie. You could make your own build of gpx with a new steps per mm, but really there is no point.
The solution:
Your slicer knows what volume of plastic it needs to extrude for a given move. It uses the filament diameter you’ve entered to do some sums to turn that into a length of filament to extrude. And that is the given GCODE. All slicers (somewhere) have an option to apply a factor to the amount to correct for over/under extrusion. Often it’s set to 1.0. In Simplify3D and Slic3r it’s called “extrusion multiplier”. You’ll have to find it in whatever software you are using. But change it a bit and see if that helps your problem. For PLA you might need to go down as low as 0.9.
A good way to select a value is to print some test cubes and set the extrusion multiplier as low as you can where you still get solid top layers