Nearly everyone wants to fly their personal tail number on their favorite aircraft.
Please add a "Change Registration/TailNum" button to the Aircraft Customize / Configuration Dialog.
(I'm flying XP11.11 and made a copy of the plane I wanted (LongEZ N28EZ) and changed the tailnum in the acf and edited the paint.png so I am good, but I see a lot of folks asking how to registration change on the LR C172SP aircraft.)