Username & Rank query

Does changing your username through the Minecraft website remove your rank?
Like for example I have the minecraft username: 23Bob
and I change it to 32wires
will i have to redo my application for the new user name or will I still have my rank. Because theres there's a system that checks server ranks and compares with username. And since the my username and the server data is different ill get banned for "hacking the system" or will i just get demoted back to guest?