How does an operator change the engine thrust rating?
Please refer to the following website, it explains the plug programming.:

http://nandang-smart.blogspot.com/2014/09/cfm56-7b-identification-plug.html

You may read:


  WHEN ENGINES ARE MOVED BETWEEN AIRCRAFT AND MAY REQUIRE A DIFFERENT THRUST INSTALLATION THIS N1 MODIFIER IS USED IN CALCULATIONS TO UPRATE OR DERATE A GIVEN ENGINE AT AN APPROPRIATE LEVEL.


You may also read


  THE THRUST LEVEL OF AN ENGINE IS CHANGED (PERHAPS MORE ACCURATELY "PROGRAMMED") BY INSTALLING A "ID PLUG" THAT SCREWS ONTO THE EEC AND CONVEYS PROGRAM INFORMATION THAT SETS THE ENGINE THRUST OUTPUT TO THE LEVEL DESIRED BY THE OPERATOR.


With respect to the thrust limit, you may display on the CDUs ( MCDUs) the FMS thrust limit page that allows the pilots to derate the TO thrust.

The following website shows for the B777 how to get access to the «  thrust limit » page:


                
            

So the pilot may change the thrust limit from the CDU, while the rating is changed by pin programming on the plug, the value entered in the CDU by the pilot is transmitted to the FMS which will ask the FADEC to reduce the thrust whatsoever below the rated value chosen by the operator by pin programming.