Hi Dave, the ATC does not need to be changed. Every airport comes with an AFCAD file (which can be edited with Airport Design Editor (freeware) or Flight1 AFX (payware)). If you change the runway numbers there, ATC will guide you to the correct runway. Please not that also the visuals (taxiway signs, runway numbering) needs to be adjusted. So in this case it is either up to the developer or some good folks who are handy with updating these files.